Good examples.

Might "fake news" be an example as well?

There's a quote, and i think it's orwell, along the lines of

"when one is speaking with a certain kind of man, one gets the impression that one is not arguing with a person, but with a wall or pat phrases and stock propaganda"

I can't find the full/correct text or a citation, but I know i've read it...

Forums everywhere end up with their own set of memes which are very effective thought-terminators. It's hard to stay engaged in serious debate in the first place, and even a couple people are usually enough to derail a discussion among "equals" to the point where nothing productive can happen.

How about when people become upset when you simply disagree with what the group believes, when it's not even hurting anyone. I have seen people act upset, and then use that emotion to justify shutting down the conversation.