Someone was too rude to me.
Why did you think it was rude?
Because the asshole doesn't even care about me
I'm glad you can know when someone is being rude or not, and you should have called him out on it. He has no right in being a jerk to everyone and you and sour the mood. You need to put a stop to him or else he'll just keep making you miserable.
I don't want to be the bully here.
I am actually agreeing with you. You should call out people who are bullying and being rude so that they won't affect other people and do them harm. Doing so doesn't make you a bully.