By this point, I groan every time Diane appears on screen. This episode is entirely skippable: Diane as its central character. She's intolerable: selfish, narrow, and self-righteous. She's basically a pure-cringe conduit for those naive and sententious Leftist sermons that most of us outgrew by sophomore year.
She has become a black hole for this show. She sucks out the life and tanks whatever narrative momentum one feels building among the other characters. Also, while the other characters are genuinely aware of their flaws, it feels like Diane only gives lip-service to self-awareness and self-deprecation. Her character doesn't seem to really believe that she's flawed. She seems to think that she's kind of awesome. Because of this, BoJack must answer to her, recount every mistake to her, etc., simply because she is somehow owed as much.
It's a Diane episode. Do yourself a favor and skip it.