They're not illegally harvesting anything. Copyright law is all about distribution. As much as everyone loves to think that when you copy something without permission you're breaking the law the truth is that you're not. It's only when you distribute said copy that you're breaking the law (aka violating copyright).

All those old school notices (e.g. "FBI Warning") are 100% bullshit. Same for the warning the NFL spits out before games. You absolutely can record it! You just can't share it (or show it to more than a handful of people but that's a different set of laws regarding broadcasting).

I download AI (image generation) models all the time. They range in size from 2GB to 12GB. You cannot fit the petabytes of data they used to train the model into that space. No compression algorithm is that good.

The same is true for LLM, RVC (audio models) and similar models/checkpoints. I mean, think about it: If AI is illegally distributing millions of copyrighted works to end users they'd have to be including it all in those files somehow.

Instead of thinking of an AI model like a collection of copyrighted works think of it more like a rough sketch of a mashup of copyrighted works. Like if you asked a person to make a Godzilla-themed My Little Pony and what you got was that person's interpretation of what Godzilla combined with MLP would look like. Every artist would draw it differently. Every author would describe it differently. Every voice actor would voice it differently.

Those differences are the equivalent of the random seed provided to AI models. If you throw something at a random number generator enough times you could--in theory--get the works of Shakespeare. Especially if you ask it to write something just like Shakespeare. However, that doesn't meant the AI model literally copied his works. It's just doing it's best guess (it's literally guessing! That's how work!).