"You're a stupid idiot!" is toxic? Really?
Will an lexiconic arms race develop to bypass the AI, kind of like the "insult battle at the theatre" scene from "Cyrano de Bergerac"?
"Oh no, Sir, you are too simple! You could have said, 'The alleged positive quality of your perspicacity is egregiously mendacious.'"
If nothing else, it could serve to increase literacy.