There's two parts here.
The first:
> it was a fair use because all Anthropic did was replace the print copies it had purchased for its central library
It is only fair use where Anthropic had already purchased a license to the work. Which has zero to do with scraping - a purchase was made, an exchange of value, and that comes with rights.
The second, which involves a section of the judgement a little before your quote:
> And, as for any copies made from central library copies but not used for training, this order does not grant summary judgment for Anthropic.
This is where the court refused to make any ruling. There was no exchange of value here, such as would happen with scraping. The court made no ruling.
I believe you are misinterpreting the ruling. Remember that a copyright claim must inherently argue that copies of the work are being made. To that end, the case analyzes multiple "copies" alleged to have been made.
1) "Copies used to train specific LLMs", for which the ruling is:
> The copies used to train specific LLMs were justified as a fair use.
> Every factor but the nature of the copyrighted work favors this result.
> The technology at issue was among the most transformative many of us will see in our lifetimes.
Notable here is that all of the "copies used to train specific LLMs" were copies made from books Anthropic purchased. But also of note is that Anthropic need not have purchased them, as long as they had obtained the original sources legally. The case references the Google Books lawsuit as an example of something Anthropic could have done to avoid pirating the books they did pirate where in Google obtained the original materials on loan from willing and participating libraries, and did not purchase them.
2) "The copies used to convert purchased print library copies into digital library copies", where again the ruling is:
> justified, too, though for a different fair use. The first factor strongly
> favors this result, and the third favors it, too. The fourth is neutral. Only
> the second slightly disfavors it. On balance, as the purchased print copy was
> destroyed and its digital replacement not redistributed, this was a
> fair use.
Here one might argue where the use of GPL code is different in that in making the copy, no original was destroyed. But it's also very likely that this wouldn't apply at all in the case of GPL code because there was also no original physical copy to convert into a digital format. The code was already digitally available.
3) "The downloaded pirated copies used to build a central library" where the court finds clearly against fair use.
4) "And, as for any copies made from central library copies but not used for training" where as you note Judge Alsup declined to rule. But notice particularly that this is referring to copies made FROM the central library AND NOT for the purposes of training an LLM. The copies made from purchased materials to build the central library in the first place were already deemed fair use. And making copies from the central library to train an LLM from those copies was also determined to be fair use.The copies obtained by piracy were not. But for uses not pertaining to the training of an LLM, the judge is declining to make a ruling here because there was not enough evidence about what books from the central library were copied for what purposes and what the source of those copies was. As he says in the ruling:
> Anthropic is not entitled to an order blessing all copying “that Anthropic has ever made after obtaining the data,” to use its words
This declination applies both to the purchased and pirated sources, because it's about whether making additional copies from your central library copies (which themselves may or may not have been fair use), automatically qualifies as fair use. And this is perfectly reasonable. You have a right as part of fair use to make a copy of a TV broadcast to watch at a later time on your DVR. But having a right to make that copy does not inherently mean that you also have a right to make a copy from that copy for any other purposes. You may (and almost certainly do) have a right to make a copy to move it from your DVR to some other storage medium. You may not (and almost certainly do not) have a right to make a copy and give it to your friend.
At best, an argument that GPL software wouldn't be covered under the same considerations of fair use that this case considers would require arguing that the copies of GPL code obtained by Anthropic were not obtained legally. But that's likely going to be a very hard argument to make given that GPL code is freely distributed all over the place with no attempts made to restrict who can access that code. In fact, GPL code demands that if you distribute the software derived from that code, you MUST make copies of the code available to anyone you distribute the software to. Any AI trainer would simply need to download Linux or emacs and the GPL requires the person they downloaded that software from to provide them with the source code. How could you then argue that the original source from which copies were made was obtained illicitly when the terms of downloading the freely available software mandated that they be given a copy?