Why would you be allowed to share copyrighted works without a license from the rights holder that gives you that right?

Depends how you got it and what format it’s in. You would have to give more info but generally, public facing is fine. If you need an account to access the data, it’s probably not okay to share it.

That being said, if you look at kaggle, there’s a bunch of stuff on there that you wouldn’t expect. You can kind of just upload it and hope for the best.

No

Just say it’s for AI and you’ll have scores of people here defending you

by sharing you are copying that copyright material, and you are not the rights holder, are you? So no, you are not allowed to do that.

You can’t license other people’s work. And you’re doing everyone a disservice if you attach some wrong license to copyrighted material. Someone might believe you, use it under those conditions and get sued. Please don’t do that. It’s not only copyright infringement, but also being disingenuous to the people downloading that content. The correct way to re-distribute copyrighted material is either ask for a license and attach what they gave you, verbatim. Or plainly say it’s not shared legally, or don’t attach any license. Don’t say it’s copyrighted and illegal to share, but also don’t say anything that isn’t correct, just put the files somewhere. (The latter 2 options aren’t legal to do. But at least you don’t claim anything that isn’t true.)

This is what brought the pirate bay guys in jail, why the scihub girl is seen as a criminal by the US, and what caused reddit founder Aaron Schwarz suicide