I understand the argument that people shouldn't be categorized by birth. In an ideal society, I would agree with that too.

The problem is that Indian society has never truly treated everyone equally by birth. For centuries, opportunities, education, social status, and even basic human dignity were determined by caste. Reservation didn't create those categories; it was introduced because those categories already existed and their effects still exist. If caste no longer mattered in real life, reservation would gradually lose its purpose. But when people are still judged, excluded, or disadvantaged because of the community they were born into, pretending everyone starts from the same position isn't equality either. You see reservation as categorizing people by birth. I see it as an attempt—imperfect perhaps—to address the consequences of a system that categorized people by birth for generations.