Your handling of the PHD situation sounds perfect and it seems like we're in agreement.

I want to reiterate you will never be in a situation where everyone is respectful even if it's a professional setting. You also can't control what other people do so there's no point expecting people to give criticism respectfully or trying to teach people how to do so - you can't correct someone's behavior if they don't want to change it.

Every time I catch myself wanting to say "people should act like xyz" I stop myself and think "I will react a different way when someone acts like xyz" instead if I'm not happy with how the situation went. Especially if I've already expressed my feelings and someone has ignored them and still acts in a way I don't like.