Earlier quoted context omitted.
So, does this mean that people can simply argue in court now (if they were to be prosecuted for downloading media via bittorrent) that it is fair use if they used it to train a local model on their machine?
People could always simply argue in court that their torrenting was free use. If you're just some nobody representing yourself instead of an expensive lawyer acting on behalf of a large company, maybe the judge will even try to be extra nice when he explains why the argument doesn't hold water.
The thing everybody ignores about this is context.
Suppose you upload a copy of a work to someone else over the internet for . Is it fair use? That has to depend on the reason, doesn't it? Aren't there going to be some reasons for which the answer is yes?
The "problem" here is that the reason typically belongs to the person downloading it. Suppose you're willing to upload a copy to anyone who has a bona fide legitimate fair use reason. Someone comes along, tells you that they have such a reason and you upload a copy to them. If they actually did, did you do anything wrong? What did you do that you shouldn't have done? How is this legitimate fair use copy supposed to be made if not like this?
But then suppose that they lied to you and had some different purpose that wasn't fair use. Is it you or them who has done something wrong? From your perspective the two cases are indistinguishable, so then doesn't it have to be them? On top of that, they're the one actually making the copy -- it gets written to persistent storage on their device, not yours.
It seems like the only reason people want to argue that it's the uploader and not the non-fair-use downloader who is doing something wrong is some combination of "downloading is harder to detect" and that then the downloader who actually had a fair use purpose would be able to present it and the plaintiffs don't like that because it's not compatible with their scattershot enforcement methods.