"In the group text, they joked that I would go out and play basketball all day, only listen to rap and hip hop, coming back late at night, and even joked that they should all move out because of me..."
Would this be an okay use of humor to ease their discomfort?
Having said that, firstly, understanding why a bad behaviour happens is important in stopping it: maybe students should meet their roommates earlier, or get introduced to them over the phone, or get pamphlets titled "How Not To Alienate The Person You Will Live With For The Next Year", or something.
Secondly, the OP is talking about people who were raised in a totally different culture. "Black" in the context you're talking about presumably means black Americans, who live in the same country as you, speak the same language as you, and get the same TV as you. As someone from outside America, I'm quite happy that the cultural differences between us exist, because they make life interesting - however, they can be an obstacle to communication.
Just sounds funny to me. Almost like a history of oppression is an integral factor in this, and joking about the diligence and work ethic of a group that's found huge success via those is different from joking about a group that's been literally enslaved, marginalised, and overtly oppressed by the group the jokers belong to.
I wonder if his roommates were attempting to give him some social cues about what kind of behaviour they wanted and/or trying to ease their own discomfort about living with someone from a different culture.