I'm pretty against big money-grabbing companies as you put it, but I'm happy to license all my photos, code, and art with public domain licenses, even if it benefits those companies. Because I think it's the right thing to do. Ultimately, companies use copyright as a weapon to oppress the speech and learning of regular folk.
If some kid who's trying to learn coding sees a function I wrote, they should be able to copy it wholesale if it pleases them to do so. If somebody in school is learning to make hobby games while they're supposed to be doing homework, they should be able to take a bunch of sprites from nintendo games and make the story about spider-man if they want to. they should be able to share that game with other people, and even sell it.
If meta uses artifacts I create to train their AI, that's a small price to pay for doing what's right for people who are just trying to learn and express themselves naturally.