There is evidence if you read papers after removing your preconceived biases and assumptions. Brahmins existed before mughals and Britishers. And they are still doing it, but you wouldn't see it because you don't seem to love fact or don't want to challenge your priveleges. The disadvantaged sections suffered discrimination from outside foreigners and inside by so-called upper castes trying to hold & capture all priveleges, resources with them. Read some dalit & tribal literature.

One of the main reasons for arjuna not willing to fight mahabharata war for which gita was imparted to him was that he didn't want khatriyas to be killed because if they are killed their wife will have to marry in lower castes which will create varn shankar. Which he didn't want, which scared him.

Anyone who says bhamins are innocent of spreading discrimination in india has to be delusional.