Yes, it proves that caste system was corrupted during Buddha's time, at least in the part he was living in, which was nepal and northern UP. But the distinction should be made that he only criticized it being hereditary, so he supported the original pure form of caste system. Let the self hating hindus be aware, that Buddha, the foremost intellectual of the past few millennials supported the caste system in its original form.
Are you really sure that Buddha supported ANY caste system (even if it was the original caste system)?
What was this original caste system and why it was beneficial to kept it alive?
Did Buddha introduced that original caste system in Buddhism too?
You can read the scientific study on the caste system by Harvard Medical School here:
https://hms.harvard.edu/news/geneti...cient-india-began-about-2000-years-ago-8-9-13
I read the research. I think the "title" given to this research in this article is false.
The article is written by Mr. Carolyn Y. Johnson, who gave this title of "Caste System in India".
While the research was done by Professor David Reich of Harvard Medical School, and his research was not about the caste system, but about the "North India" and "South India" divide. The details of this research is present here:
https://www.boston.com/news/science...m-in-ancient-india-began-about-2000-years-ago
And here one reference from this research which makes it clear that it was not about caste system, but about North and South divide:
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Reich has examined hundreds of thousands of regions in people’s genomes and found evidence that the northern and southern populations mixed around 1,900 to 4,200 years ago.
//
Nowhere in this research Reich said that he is researching about 4 Varnas (Brahmins, Kshatariyas, Vaishyas, Shudars...and the 5th one Avarnas, the untouchable Dallits). But whole research is about North and South.
I believe that this research is incomplete as it didn't consider the Issue of slavery in India.
In ancient India, slavery seems to more common and "DAS" and "DASI" system was widespread.
And the Indian masters were sleeping with large numbers of Dasies, and those Dasies belonged to other Varna/Jati. Therefore it could have also effected the admixture in ancient India.
But then came Buddha, who criticized the slave system and then Ashoka (follower of Buddha) abolished the Bazars of slavery for the first time in Indian History (actually it happened for the first time in Human History that slavery Bazars were abolished).
Therefore, those Bazars of slavery could have been a major reason of admixture before Ashoka. The time line of this research also fits upon Ashoka as he came about 2200 years ago, and gradually the slavery reduced after him.