There is no natural selection going on here. People are born into a caste and, for all intents and purposes, their caste identity is fixed for the rest of their lives. The idea that these people have somehow developed a "higher IQ" over "generations" simply by being born to a particular caste makes no sense.
Furthermore, the arguments made in the article have nothing to do with poor performance, (possibly) correlating with a lower IQ. The article details specific examples of antisocial behavior by upper caste Indian workers against their lower caste peers.
If members of a high caste are guaranteed wealth and many children, then there is no selective pressure for intelligence.
Likewise, if lower caste members struggle to survive, then there is a strong selective pressure for intelligence and problem solving.
There absolutely no evidence of some "selective pressure for intelligence" in human societies.
Please keep eugenics and similar out of HN.
You're missing the point completely. Equal opportunity has been replaced by equal outcomes - except for the 1%