When chandalas are mixed caste then they worship Hindu gods, what is chandalas relation with Hinduism. Are chandalas foreigners.
As per Mahabharata: Anusasana Parva:
If a Sudra unites with a woman belonging to the foremost of the four orders [i.e. Brahmana], the son that is begotten is called a Chandala.
So Chandala is a mixed-cast. There are many mixed-casts due to Anuloma and Pratiloma marriages. Thus, Chandalas and other mixed-casts are not foreigners.
The definition of Chandala being born of a Sudra father and a Brahmana mother is not correct. These fanciful Smriti concepts are clearly wrong and are against the Vedas. This is clear from the Chandogya Upanishad definition of Chandala.
Those whose conduct here has been good will quickly attain a good birth (literally womb), the birth of a brahmin, the birth of a Ksatriya or the birth of a Vaisya. But those whose conduct here has been evil, will quickly attain an evil birth, the birth of a dog, the birth of a hog or the birth of a chandala.
Chandogya Upanishad V.10.7
As you can see Chandogya Upanishad is specifying conduct as the reason for different births. It has nothing to do with the caste of the father or the mother.
What does the Chandogya Upanishad verse mean?
It has nothing to do with the caste system invented by the Smriti writers. It means that depending on the amount of good conduct a person will be born to parents of high Sattva Guna (Brahmin), to parents of middling Sattva Guna (Ksatriya) or parents of high Rajasa Guna mixed with some Sattva Guna (Vaisya). The vast majority of persons with neither good nor bad conduct will be born of parents who do not have the gunas of Brahmanas or Ksatriyas or Vaisyas but whose conduct is not as bad as that of animals.
Those whose conduct has been exceptionally bad without any redeeming feature will have animal parents or human Chandala parents. This suggests that Chandala is defined as a person whose conduct is like an animal.
Why do the Smriti authors invent such fanciful tales?
The reason is that the Smriti authors were seeing a torrent of inter-varna marriages. They had a choice. They could point out like Yudhisthira that the whole hereditary caste system is no longer valid or they could invent new castes. They chose the second option.
I am posting Yudhisthira's statement.
Yudhisthira said, " In human society, O mighty and highly intelligent serpent, it is difficult to ascertain one's caste, because of promiscuous intercourse among the four orders. This is my opinion. Men belonging to all orders (promiscuously) begat offspring upon women of all the orders. And of men, speech, sexual intercourse, birth and death are common. And to this the Rishis have borne testimony by using as the beginning of a sacrifice such expressions as -- of what caste server may be, we celebrate the sacrifice. Therefore, those that are wise have asserted that character is the chief essential requisite ... whatsoever now conforms to the rules of pure and virtuous conduct, him have I, ere now, designated as a Brahmana.
Mahabharata Aranya Parva Section CLXXIX
I feel obliged to answer the remark made in the comment section even though it was a low level personal attack. The smriti writers clearly savaged the Vedic Rishis by discarding their conception of the Varna system. These medieval writers introduced dozens of 'varnas' not in the Vedas, added the idea that marriage between people of different Varna give rise to a third varna. None of these ideas are there in the Vedas.
It is these smriti writers who dumped the Vedic ideas about Varna. Can anyone show any deviation from the 4-Varna system in the Vedas? Can anyone show that the idea that the marriage of 2 persons leads to children of a third Varna is in the Vedas? The ideas of the smriti writers are also in variance with the 'guna and karma' explanation of Lord Krishna.
So whether I know less or more than these writers about the Vedas is immaterial. The question that needs to be asked is whether these Smriti writers who cooked up fanciful schemes in disagreement with the Vedas know more about the Vedas than Lord Krishna.
A Hindu is under no obligation to accept blindly the views of anyone. Even Lord Krishna does not demand blind acceptance of His teaching in the Gita:
...Reflecting on this entire teaching, do as you think fit.
The only obligation that a Hindu has is to Truth. The reason for that is given in the Upanishads.
satyam eva jayate nanrtam..
Truth alone conquers, not untruth.
Mundaka Upanishad III.I.6
These Smriti writers have done a great deal of disservice to Hinduism by dumping the Vedas.