> Why should I care?

AI training is fair use. For pirating books, they probably calculate that the fine will be lower than their profits.

Assuming you're putting videos on YouTube, you should care because they have leverage over you and can ban you.

You seem to imply some kind of moral terms or reasons based on principles but that's not how corporations work. And either way they will get a pass because their stuff is extremely valuable for intelligence agencies and the military.