> Is it theft?

Well we certainly didn't get paid for it, and now our livelihoods are at stake. So yes.

Who's?

If you're a writer whose work people enjoy to read, they will still read it.

If you're a painter whose paintings people enjoy to see, they will still look at them.

If you're a musician people enjoy listening to, they will still listen to you.

Nobody's money is being taken here. It's not like people are prompting "Give me xyzsparetimexyz's book cover to cover".

Only think that's taken from someone is the idea that they have the right to own a piece of information.