there’s still no reason you can trust that the post I referenced actually existed

Yes there are. I've seen plenty of posts like that, so it's plausible. It could be verified without too much effort, so even though I'm not going to go to the effort, it would be a risky lie to tell, a different lie would make much more sense. There's not a lot of reasons for you to write all this other than being actually frustrated with people's sentiments on this issue, and considering that the apparent strength of an argument isn't likely to change many people's minds here anyway, the emotional logic for that to be a deception doesn't really check out.

It’s hard to say that misinformation is made worse or better by AI, people who want to lead you somewhere wrong will still do it.

I would say that the big difference is the depth of misinformation, especially in the context of informal writing. Someone can have an agenda and try to work out how to manipulate people in the direction of their agenda. Someone can want to fuck with people and tell arbitrary lies for their amusement or feelings of dominance. But in all those cases, what they say is still a product of who they are, what they are thinking and how they are feeling, and that information comes through in one way or another. For all of that subtle information about the state of people to be buried in noise all coming from the same source is a terrible thing.