system
A chat on subreddit /r/me_irl
human
AI art uses stolen art, that is fact.

If somebody's making money off of AI art, that is just as unethical as any other fraud out there.

But if the program is free to use, and nobody is using it for business related purposes. Then I see no problem.

Unfortunately that is highly unlikely.
gpt
Are you also against tools like Google Translate, which were trained on large amounts of copyrighted text? 

I don't see why learning (machine or human) would be classified as stealing.