The em dashes are fine.

If someone gives them shit about their writing, that's on the critic for being shitty. If they use AI to write, that's on them for being fake. But, to write online at all requires being ready to have people be shitty to you and ideally not reacting in a way that makes the situation worse. Sounds like they need work on that part.

Anyway it is basically always possible for someone to find something legitimately bad about anything a person does. The question is, how much of an issue is that? Not much actually. So you have flaws. Fine, just be flawed. It had no affect on your life beyond your reaction to the attack. And putting aside that reaction is a prerequisite for learning anything useful (or discerning that there is nothing to learn) from the experience.

Good people will trust good intentions through the flaws, while shitty people will write off your work and your intentions because of the flaws (and try to make sure you feel bad about it in the process). But it's always they're too weak to express disagreement maturely, or sometimes because they're bitter and threatened by your good intentions directly. Either way, it's their flaw, not yours.

I don't think that you can successfully dismiss an obvious AI writing marker with

"No these are fine, now look over there!! <lotsoftext>"

Pay no attention to the man behind the curtain?