Just when you thought a heavily racial show (ABC’s mixed-ish) that loves to turn racism against white people into humor couldn’t sink any lower, you end up with Tuesday’s episode, “Walk This Way,” in which main character Paul (Mark-Paul Gosselaar) pathetically uses his “white privilege” in a desperate attempt to make his racist black sister-in-law Denise (Christina Anthony) like him. (If you remember, Denise is the one who loves “disappointing white people.”) At the start of the episode, we see a montage of all the ways Paul has tried to please Denise over the years and how much Denise disdains him. “