If it's pretty fucking simple, can you point to the statement in the linked post that supports this assertion? What it says is "According to the notice, the district court ruled that using the books to train LLMs was fair use", and while I accept that this doesn't mean the same would be true for software, I don't see anything in the FSF's post that contradicts the idea that training on GPLed software would also be fair use. I'm not passing a value judgement here, I'm a former board member of the FSF and I strongly believe in the value and effectiveness of copyleft licenses, I'm just asking how you get from what's in the post to such an absolute assertion.

It's pretty fucking simple: a judge needs to decide that, not armchair lawyers on HN.