ISKCON has more or less denied being Hindus. They claim to use some Hindu scriptures but their translations are sometimes different from translations by established Hindu sources.
Does their work qualify as authentic Hindu scriptures?
Here's what I will say about this with all due respect. I had been a member of ISKCON for several years during my undergraduate degree (no longer one). My observations are as follows:-
1) ISKCON is a highly anglicized (almost Christianized) version of Vaishnav movements of the olden times (and by that I mean movements of Sri Ramanuja, Sant Tukaram and other Vaishnavas). Why is this an issue? REMEMBER:- Hinduism has always believed in multiple aspects of single unified divinity i.e. One God with multiple manifestations. People worship the manifestation which closely resembles their own spiritual self. ISKCON tends to juxtapose this to ONLY ONE GOD and OTHERS ARE AT HIS BECK-AND-CALL and somehow inferior to HIM. That becomes almost monotheistic and to me, frighteningly scary. Hinduism is democracy and monotheism is dictatorial. I believe in Shri Krishna myself
2) They have denigrated the Vedas to a worse extent. They use Vedic Shrutis and scriptures only to prove their affiliation to Hinduism and to claim the authenticity of their own cult but when it comes to scriptural authority, since the Vedas are backbone of any Hindu lifestyle across India (and beyond), all knowledgeable Hindus (even those who haven't read the Vedas) accept Vedas as supreme. Not so with ISKCON. ISKCON just considers Vedas as chants and hymns to inferior deities
3) ISKCON Bhagavad Geeta verses are the same as the actual Bhagavad Geeta verses if you read them in SANSKRIT but how many of us actually recite the Shlokas and mantras these days? Mantras and Shlokas have actual power, efficacy, and potency. We just read the translation. That's where the brainwashing and cult worship begins. The purports are way too long that deviate people from core values of the verse
4) Thirdly, they have completely forged accounts of events such as Raas Leela etc. in their Srimad Bhagavatam books almost to a degree of making such a character as Krishna's---an illicit playboy. According to them, Shri Krishna is even superior to Shri Vishnu (who is Vedic God) when everyone outside ISKCON knows its vice-versa. In the beginning, there was Trinity and then all the others incarnated. This is done to mess up Hindu timelines and scriptural understanding on purpose I assume
5) Some of the folks have mentioned that they are anti-Shaivites. That is TRUE. This is evident in their literature clearly. They are anti-Shaivites and anti-Brahminical. However, they have done well to masquerade these days as those that worship Shiva to get to Krishna (who is eventually superior). This is done just to attract more people into the cult
6) ISKCON was and still is notorious for sex racquets and other activities quite like Osho's ashrams were. Child trafficking, prostitution etc are some of the major concerns it has had to deal with in the past. Search YouTube and you will find real-life conspiracies of ISKCON priests at high echelons involved in gross scandals. Most of this is influenced by the concocted meaning of scriptures
7) ISKCON is also notorious for breaking up married couples who are true seekers of spiritual path as a couple. I have heard numerous stories of divorces because one amongst the couple suddenly expects to live a celibate life after having followed ISKCON lifestyle for a while just because of misrepresented Hindu material on celibacy in their books
8) Women and children (especially women) are considered inferior in this cult. Unlike Shiva and Shakti who are equal halves of Unified divinity, the concocted understanding that ISKCON promulgates is that Radha serves Krishna or is subservient to Him. There are modern-day ISKCON gurus who are inspired to make more followers so they would deny this but in their core culture, this is a fact
9) Their (ISKCON's) present version of scriptures are tainted with adulteration as the publishing authority lies with that faction of ISKCON which is run from America. This faction was responsible for apparently killing its founder Srila Prabhupada. There is a power struggle going on within ISKCON and only renegade temple is the Bangalore's ISKCON at West of Chord Road Rajajinagar
10) Even then, Srila Prabhupada's ideology was also against core Hindu belief systems but now due to the internal conflicts between two different ISKCON entities, it has grown worse especially in the literature publishing, profit sharing etc.
11) Other great saints of ancient India such as Adi Guru Shankaracharya are vilified (as Mayavadi) by ISKCON literature Srimad Bhagvatam even though it isn't part of original Srimad Bhagavatam
I would suggest read authentic scriptures from places like Geeta Press Gorakhpur and other reputed local INDIAN authors with strong Hindu foundations and beliefs only. Don't read the translation from international writers as there is bound to be prejudice, the malice of forethought etc. Hope this helps. Refrain from joining cults and channels and do your own homework. Refrain from reading about Hindu material on the internet and especially Wikipedia.
This is not to hurt any current followers but I'm merely trying to explain the contrasting beliefs between actual Hindu belief systems and those of cults. I'm against any cult and choose to learn this on my own from what I consider the authentic representation of our scriptures which is the least adulterated way of learning about our culture. A Guru is always helpful if you find a genuinely knowledgeable one just as our own scriptures say that "Just as the Guru tests its prospective Shishya (disciple) so must a Shishya (Disciple) test his Guru in order to identify Guru's capabilities and whether the Guru is able to guide him to the right path". It takes time and effort which no one wants to put today. I would also encourage people to learn Sanskrit and Shuddh Hindi (untainted with Urdu and Persian words) as well as Tamil. Thanks! Appreciate your motivation
ISKCON is a Gaudiya Vaishnava Hindu religious organisation. They are in fact Hindus. But they consider Sri Krishna as the supreme lord (Swayam Bhagawan) and claim to follow the Mahabharata and Bhagawath Gita. They describe Sri Krishna as the source of all the avatars of God. It was established to propagate spiritual knowledge, consciousness of Krishna, The principle of reincarnation, sankirtana movement etc.
But their beliefs contradict even basic ideas of Hinduism. They are basically against Shaivates.
Their version of Hindu scriptures are not accurate. I have personally read their publications and observed that they generally deviate from the normal content to glorify Sri Krishna.
Though the main story remains the same, if you read deeper, many things seems to be different, which does matters.
Also refer this link http://avalon.wz.cz/Dusevni_rust/Distortionsofscriptures.htm
I think it is better not to use iskcon for reference or citations.
Hare Krishnas are Hindus.
His philosophical teaching of achintya bhedabheda which are based upon Hindu scriptures.
When their philosophy has roots from Hindu scriptures then Yes, ISKCON versions of Hindu scriptures qualify as Hindu scripture.
In Distinguishing Srila Prabhupada's Original Books from Changed Ones, there is a reference which says Parabhupada Himself said that His books which are printed are not the original ones.
Srila Prabhupada's books can be broken into 3 basic categories:
1) Books that he himself directly wrote.
2) Books that are compilations of his statements coming from lectures, letters and conversations etc…( these were compiled specifically under his instruction by his disciples, such compilations were put together in his physical presence.
3) Book compilations that were put together after his physical departure.
The significant point which is worth noting is that even though some books are titled pre-1978, edition they may still have unauthorised changes to them. To properly understand this it would be in the reader's best interest to read in the Vedabase the 1977 conversation titled "Rascal Editors". In this conversation with Srila Prabhupada it is very clear that his books were being changed without his authorisation even in HIS PHYSICAL PRESENCE!!! Therefore the question which should naturally arise is "among the pre-1978 books, which ones are authorised and which are not?" This basically is the crux of the matter.
So, it is far better to focus on the original versions and rather edited ones.
The same website Book Archive Original pre-1978 Books has all the original books by Prabhupada.
First of all I think this question is more suitable for meta rather than main site. But since you have asked, so here is my answer. First we should know What is ISKCON?
The International Society for Krishna Consciousness (ISKCON), otherwise known as the Hare Krishna movement, includes five hundred major centers, temples and rural communities, nearly one hundred affilated vegetarian restaurants, thousands of namahattas or local meeting groups, a wide variety of community projects, and millions of congregational members worldwide. Although less than fifty years on the global stage, ISKCON has expanded widely since its founding by His Divine Grace A. C. Bhaktivedanta Swami Prabhupāda in New York City in 1966.
ISKCON belongs to the Gaudiya-Vaishnava sampradāya, a monotheistic tradition within the Vedic or Hindu culture. Philosophically it is based on the Sanskrit texts Bhagavad-gītā and the Bhagavat Purana, or Srimad Bhagavatam. These are the historic texts of the devotional bhakti yoga tradition, which teaches that the ultimate goal for all living beings is to reawaken their love for God, or Lord Krishna, the “all-attractive one”.
So, it is a Hindu sect that treats lord Krishna as supreme. And since on this site all Hindu sects and their Acharya works (specifically their commentary and translation on old scriptures) are valid, so surely we can use ISKCON works here to cite sources.
This topic has been discussed on meta previously and here is the list of useful resources.
Their work doesn't qualify as "scriptures", we already have scriptures.
But commentaries produced by acharyas from that sampradaya can also be used as references just like other acharyas of other sampradayas. Their opinions can be useful too.
Unless they are talking about something which doesn't have any scriptual basis, I don't see what the big problem is.