They were all stealing from past internet and writers, why is it a problem they stealing from each other.

Nobody is saying it's a problem.

This. Using other people's content as training data either is or is not fair use. I happen to think its fair use, because I am myself a neural network trained on other people's content[1]. But, that goes in both directions.

1: https://xkcd.com/2173/

because dario doesnt like it