First rule of comedy: don't kick downwards. It's essential if we want to collectively get over our intolerance.
An anecdote: someone like Dave Chappelle is wildly popular on both the left and the right. Several friends of mine on the right devour his specials like a gourmet buffet. So when Chappelle gets up on stage and talks about his experiences with racism, police profiling, and inequality (as he did on yesterday's SNL monologue [0]), those same people on the right listen. They hear him. It moves the needle of justice forward by reaching an audience who otherwise wouldn't necessarily hear these stories.