In the US, there seems to be more stress on diversity. I think that approach started due to constitutional reasons, but it has become a creature of its own. The value of enforced diversity is questionable. Students can segregate themselves. Affirmative action is patronizing and it might lead to the beneficiaries and others looking at themselves as undeserving. But it is a trade-off. Fixing the gap in opportunity versus being looked at as a quota candidate.
Other than that there are two lines of argument, that affirmative action is not required and that it does not work. The article does not claim the first but flips the argument to unfair treatment of whites. There are poor whites also but as a whole they continue to have advantages. The specific case mentioned is problematic. I am not going to enumerate the historical injustices and their continuing effect but the system was rigged against minorities in many ways, often at an organized level. In general, someone or something is always interfering with the system and it has never been totally fair or meritocratic. One very obvious example is legacy admissions. (A study of 30 elite institutions found that the children of undergraduate alumni (“primary legacies”) were 45.1% more likely to get in.) There are less obvious channels. Not that two wrongs make a right but I don’t see this as a wrong. Some could say that government intervention is worse, which I would disagree with.
The article does claim the second. It specifically points to the theory of mismatch which is debated. I have seen articles and studies saying Yes and No. The results seem to be mixed, creamy layer problem is there everywhere but there is usually some positive impact. It is not ideal and it ignores the fundamental issues in both the US and India. But those systemic issues are not getting fixed anytime soon and I think in the absence of it, the situation would be worse. An interesting article on it: https://www.foreignaffairs.com/articles/2015-03-01/does-affirmative-action-work