My two cents on racist Allura. I actually really liked her reaction, before that arc she'd come off as rather bland to me without any flaws. Her reaction to discovering Keith's heritage felt very human. She was hurt badly and she lashed out against someone who didn't deserve it. Her coming to terms with her feelings not justifying her actions on her own felt like growth as a character and in her fight against Zarkon. She came to realize she wasn't fighting the Galra but the empire.