If you’re not, and I say this in good faith, take your own advice around your tone. Making assumptions about other people, and then doubling down when they correct you, comes across as a kind of horrible I doubt you truly are.
I still like ‘em!
2.) I'm comfortable with varied comma stylization.
3.) My personal usage of the em-dash hasn't changed in a few decades and I don't see it doing so just because a bunch of folks only just recently learned it exists.