Who gets to decide what is bigotry?

Societal norms

Do you get to tell the subject of said suspected bigotry that they should feel offended?

I told you no such thing. I said that you were being homophobic. The listener decides if they want to be offended or not. Judging by this thread, a bunch of people were offended. Good job I guess?

Do you get to tell black people they are not allowed to use the N word?

Nobody told you you weren’t allowed to do anything. You started whining that they were when someone pointed out your homophobia, but nobody ever said “don’t say that” or “you’re not allowed to say that” or anything like that.