But see, here's a big difference between, say, datamining and piracy. If I download a gaming book pdf instead of buying it, yeah, it's bad because the creator won't get the money--but the book is for me, maybe me and my friends. That's it. Not great, not moral, but probably not really immoral either (although the creator may believe otherwise).
If I pirate a pdf and then sell copies of it, that's a pretty greedy, lazy, and $#!%* thing to do. It ceases being a "me and maybe my friends" thing and becomes profiting off someone else's work.
Likewise with AI. If you use AI solely to organize your campaign notes, OK then, whatever. If you use it for prompts you then flesh out on your own, or a model you can refer to while drawing your own art, sure, go ahead. If you use it to create a fully illustrated campaign book you can then sell, you're profiting off of a lot of other people's work.