It's not to make AI training easier; AI training is already happening. It's perfectly easy for them.

It's to preserve our heritage and knowledge. Automatic copyright is what causes information to be lost. I don't suppose you're going to submit your comment to LoC or otherwise keep it available for 70 years after you die? Does everyone remember to submit their code they publish?

We're not losing books because of AI companies. We already lose them because the law makes it so only groups like Anna's Archive can save them.