I don't think he's acting like an emo fan in that thread, I would use a word that starts with r to describe that thread
Not liking hip hop is no more racist than not liking K-pop is. Some people just don't like sounds of certain types of music. Not everyone is going to like emoviolence either.
Saying that hip hop culture "promotes crime and violence" is 100% a racist dogwhistle, it's like saying listening to emoviolence will make you want to commit mass shootings.
90s gangsta rap (the type I'm most familiar with because that's what was popular in my [almost entirely white] high school) definitely DOES glorify those things. I can't think of any emoviolence songs glorifying mass shootings, or that are even about that topic at all come to think of it.