Anything can be joked about. But it's best leaving those topics to those who live them. Leave trans jokes to trans people. Leave gay jokes to gay people. Leave black jokes to black people.
"Wait, that's not fair, then how could I, as a straight white male, make any jokes?" ..... You can if you are a comedy genius. Stop hitting low hanging fruit. If you want to beat around identity comedy, trust me, there's lots of make fun of straight white men on.
* If black people can joke about getting nailed by cops on racism, make jokes about how you don't. (As long as it isn't bragging and is genuinely comedy, it works) ...... * If a gay person talks about how hard it is to find people on Grindr for a commitment, make jokes about dating in the way of "Gay guys have issues about finding commitment on Grindr, but let me tell you something about my experience in other dating apps"..... etc.
These comedians just need to take a talking point, and turn it onto themselves as the subject. They take other experiences they don't have, and sometimes use it to punch down.
It's not hard. Everyone has experiences with everything. Everyone experiences them differently based on who that person is. Tell it from your own perspective, not from some made up strawman point. Once you figure that out, make a few jokes about it, and boom. You avoid being an asshole.
Like George Carlin once said - anything can be funny it just depends on context