

It was a perfectly reasonable response.
Maybe you haven’t noticed, but when a person does not like facts that match the reality they have (co-)constructed they must reject the fact. When they can’t do that they seek to diminish the fact by attacking the messenger.
This is what you have done here. It is boring and predictable.

Keep away from these people if you can. Focus on your own development. Keep grafting. Use it as motivation, rather than a reason to have your confidence knocked. Know that a lot of people bullshit. Part of bigotry is that it undermines the confidence of people that aren’t part of the in-group, thus maintaining the in-group’s position of advantage. It is drummed into rich white people at expensive schools for this very reason. I’ve no idea what things are like where you work/live, and I understand that trying to address this via hr might just be detrimental, but if they are breaking laws then get evidence and speak to somebody about it.