Woah! Piracy is not considered stealing. The MPAA and RIAA made that argument over and over and over again in the 90s and early 2000s and they lost. Thank the gods!
You would download a car!
If piracy was stealing, we'd all be waiting for our chance to watch TV shows in a queue of thousands.
Copyright violations are not theft. They never were and they never will be. Because no one is deprived of anything when something is copied. In theory, there could've been a lost sale as a result but study after study has shown that piracy actually improves sales of copyrighted works.
When an AI is trained on images that YOU—the artist—posted to the public Internet for the world to see it will either increment or decrement a floating point value by like 0.01. That's it! That's all it does.
How can that be considered "stealing"‽ It's absurd.
You bring up a great point! When someone does that: Painting a replica and passing it off as their own, what law have they violated? They have committed fraud. That's a counterfeit.
Is making a counterfeit stealing? No! It's counterfeitting. That is it's own category of law.
It's also a violation of the owner's copyright but let's talk about that too: If I pay an artist to copy someone's work, who is the copyright violator? Me, or the artist that painted it? Neither! It's a trick question, because copyright law only comes into force when something is distributed. As long as those works never get distributed/viewed to/by the public, it's neither here nor there.
The way AI works is the same as if you took a book you purchased, threw it in a blender, then started pasting chunks of words out of it in a ransom note.