If Bulgarians aren't Slavic, then it's perhaps time for the rest of them to seek a new name for themselves, because it's us that used that ethnonym first, dig?
Do you have a problem with Bulgarians?
Yeah, I do. They're the worst.
It can be hard to be considered an other when you belong to a race or place but people don't want to accept you. You would be hurt to not be accepted by others, so I think you should try to be more considerate towards people from Bulgaria.