The three comments here show why behavior like Murs goes not only unaddressed, but unpunished. Rap culture shouldn't be off limits to criticism because of race.
You are correct in that WillPostForFood other poster is mentioning rap culture, which is predominantly based on a racial and class-based culture, but they are not injecting it into the discussion as it is part of what occurred. Perhaps you're simply uncomfortable discussing the topic, which is common.
You do realize that “rap culture” revolves around a product marketed to, and bought predominately by white kids, right? I realize the term is just a dog whistle for a much less kind word, but still.. so stupid.
Fun fact: An Interscope executive's teenage daughter was/is responsible for Tupac being signed to the label. She really liked his demo and begged her father to sign him.