It isn't irrational.
The idea is that selling, or giving away art grants the consumer to sell art of his own, not a clear copy of.
So the court rationally found Anthropic guilty for acquiring copies without paying for them. But didn't charge the training, deemed fair use.
If it isn't fair use, then we may need to sue all teachers for spitting out knowledge they ultimately acquired from someone's work.
Copyright, some would say is irrational. Humans learn, that is copying, distilling in fact.
Copyright though is pragmatic: it draws a line, art will be reproduced, let's just enforce that they can't be shameless (near) identical copies. Mix it up, derive the original enough so that you aren't competing with the original author.
The only argument to ban training on copyright data is that it unfairly compete with original authors. Which stance do you take? Neither would be irrational.
I agree that the fair use argument on training data is a genie that’s not getting put back in a bottle. But:
> If it isn't fair use, then we may need to sue all teachers for spitting out knowledge they ultimately acquired from someone's work.
Is such a lazy argument and always was. A human doing something is necessarily different than a machine doing it. We can be ok with a human doing a thing and simultaneously not ok with a machine doing it.