People who never really used Twitter don't understand what a thick skin some of us developed because of it.
But they also tend to think they're inherently superior for not having used Twitter when in many cases, they're just as bad as your average bottom of the barrel Twitter reply guy troll weirdo.
They've just never faced any serious pushback for it, the way they would if they had been on Twitter. So they never learned to shut the fuck up.
And that's been a major irony in using Mastodon.