Last week, I asked, and answered, “Has this long-running series finally lost its edge, and its appetite to approach third-rail subjects?”  My answer, based on Season 22’s premiere episode on school shootings, was: “Uh, no. Not even close.” And now, another question, which the title of this week’s episode makes all but rhetorical: “Has South Park cleaned up its act?” Not when this new episode, reaching back deep into the show’s feces-fascinated history, is called “The Problem with a Poo” (pictured).