You are right. This anti "affirmative action" rhetoric is quite common among upper caste people in India. Unless OP managed to get faked documents and pretended to be from a lower caste, they absolutely did not gain anything.
In the same way you don't gain anything in the US if you change your last name from a 'black' or 'jewish' or 'slavic' last name to something 'american'. That is people treat you differently, even though legally nothing has changed.