Impossible to prove tho. You can always just claim you don't like the person for other reasons. That's why this whole 'banning caste' stuff is mostly performative imo. People will just be hostile to each other but not be open with the reason.
> You can always just claim you don't like the person for other reasons.
That's true. It's also true that there are plenty of professional contexts where people have to work together regardless of their personal feelings toward each other. Sometimes lives depend on it.