In brief, the situation is:
A rationalist has analyzed a text written in C++ into English because both look similar. He has critisized C++ for "bad grammar". Certain extremists are behind his life just because they think C++ grammar is cool!
what Bhagavan criticized in detail
what his arguments are
K. S. Bhagawan is an Indian rationalist, Kannada writer, translator and a retired professor. In 1982, his work "Shankaracharya and Reactionary Philosophy" (original title: ಶಂಕರಾಚಾರ್ಯ ಮತ್ತು ಪ್ರತಿಗಾಮಿತನ), a collection of essays, on how Adi Shankara, an 8th-century Hindu theologian, advocated caste system strongly, destroyed Buddhist viharas and was against education for women, shudras and dalits, was published. (Note: Education and Literacy are different).
Upon criticism of Bhagavad Gita this is what he told in interview:
In the Bhagavad Gita, chapter 9, shloka 32, Krishna says everyone is a
sinner, other than Brahmins and Kshatriyas. All women including
Brahmin ones, non-Brahmins and all Vaishyas are sinners. How can we
agree to this? The Shwetashvada Upanishad, which came earlier, says
everyone is the child of nectar. Vivekananda interpreted this and said
it is a sin to call anyone a sinner. So such thoughts in the Gita
should be criticised, rejected and taken out. I stand by this. There
are certainly some good things in the Gita. But there are very
dangerous elements. Krishna says he created the chatur varna, the
caste system. So that means he created upper castes and lower castes.
How can we call the Bhagavad Gita a great book in this context?
Unfortunately, there are certain self proclaimed saviors of Hinduism (an oxymoron word itself!). Without knowing anything about, they have threatened to kill Bhagawan.
Such stance has closed many doors to even rationally oppose Bhagawan's claims, because no one would want to get compared with those extremists.
whether his critique is well-founded?
Yes & No.
The thoughts from Adi Shankaracharya about caste-system and Krishna about lower birth people were not presented with relevant arguments by themselve. They din't find a need of discussing many "why"s prevalent today, which should pass the test of time. Because certain things were so trivial that they were understood during old times.
Incidentally Bhagawan analyzed in his own taste and passed the judgement.
e.g. Imagine in a country rule book, there is a quote:
"Murderers must be hanged till death."
After many centuries, due to demographic changes, English is limited up to such "rule books" only. A community evolves somewhere in Mongolia named as "Murderer" in their Mongol language. Ignorant people of those times start killing them by hanging because "Murderers" appearing in those English rule books. Of course sane people should oppose such acts.
Bhagawan is also doing that, but condemning those scriptures as well. Had he tried to pull out the real meaning, it would have avoided this criticism. His main point of opposition is for caste-based and gender based inequality.
To explain what he has got wrong, let's draw an analogy with open mindset:
The nuclear science can be used for creating atomic energy as well atom bombs. First it got evolved in US & quickly followed by Russia during 1940s. Then it got into the hands of China & even North Korea. Today many countries want it.
Until it was in hands of (then) US, it was fine because the US was self sustained, democratic/republic and responsible country. They din't use them post WW2. But as soon as it went to Russia, a nexus was created within world. When it went to China, it created even more evil nexus and now North Korea rants about using those weapons every now and then.
A country is not evil by itself, but certain kind of powers if goes unwarranted to its hand, it becomes evil.
Would we like to give away this nuclear science to all countries?
For a moment hypothetically transfer people of Russia to North Korea, North Korea to US, US to China and China to Russia. Now we can't say that weapons with US is safe and North Korea is unsafe. So differentiation doesn't happen based on country name but the psychology of people.
Similarly, certain knowledge if remained with certain level of people is good for healthy society. During old times the Varna Vyavastha (Divisions, Not Castes) & Grihasthashram (marriage) were quite well-defined. They were in sync with Swa-Dharma (self duties) for all. Since people used to follow it properly, births after births a soul will tend to remain in the same division.
Due to which the divisions started getting typecasted with certain communities, known as "Castes". Later "Castes" became the synonyms of "Divisions" like how "Countries" became synonyms of "Responsibility" in above example.
Today only castes have remained and divisions have disappeared. However Bhagawan is still relating today's "castes" with the "divisions" they were typecasted.
In today's time these divisions can be decided based on the "spiritual level" (not caste). A person by so called caste might be recognized as Brahmin, but at spiritual level he is just a Shudra. A person physically looks like a "Man" but at spiritual level he is more of a "Woman". There is nothing right or wrong in above cases. It's just a situation.
Look below at the bold part, where the divisions are differentiated based on "quality" and not "castes". This was highly missed by Bhagawan in same Bhagavad Gita.
— Brāhmaṇas, kṣatriyas, vaiśyas and śūdras are distinguished by the
qualities born of their own natures in accordance with the material
modes, O chastiser of the enemy.
— Peacefulness, self-control, austerity, purity, tolerance, honesty,
knowledge, wisdom and religiousness – these are the natural qualities
by which the brāhmaṇas work.
— Heroism, power, determination, resourcefulness, courage in battle,
generosity and leadership are the natural qualities of work for the
— Farming, cow protection and business are the natural work for the
vaiśyas, and for the śūdras there are labor and service to others.
Based on above qualities, there are still 4 divisions in today's world:
- Brahmin: priests, scientists, intellectuals, philosophers, teachers
- Kshatriya: army, sportsmen, politicians, lawyers, spies
- Vaishya: businessmen, investors, farmers, economists, artists
- Shudras: do jobs in above fields
Above list is just to give a rough idea.