You may disagree with his fashion sense, but this man is smartly dressed. I don't see any Raiders jackets, or any baggy jeans/tee-shirts. Just because his clothing is not mainstream and he is black DOES NOT make it hip-hop fashion.
While we're on the topic, note the shoes in particular, very nice, especially for a guy struggling to afford a bedroom in Oakland.
You made a dumb joke. You should consider that that joke is only funny to people who are comfortable in their surroundings and among their peers; to the lone latino or black person in the office, they come across much differently. It is a form of privilege to be able to chuckle as you toss around which rap group someone looks like they belong to; when that privilege is flexed so that it alienates coworkers, it is abusive.