Hosting copyrighted media without a distribution license is usually illegal. Very few countries allow you to just distribute proprietary disk images like this.

You can extract the images yourself from official install media (for instance, the installers you can create from within macOS) and use it for whatever personal project you want; you'd be breaking the EULA, but that doesn't mean much. You're not allowed to throw your copy on the internet, though.

Other projects I've seen download the installer images directly from Apple, something they could probably detect and block if they wanted to. That would probably be completely legal, as nobody is unlawfully distributing the files. This is different; the Docker images contain a copy of macOS.

Apple could probably take this project down any time they want to, but if they wanted to they probably would've already.

I’m not a lawyer, but pretty sure unauthorized redistribution of copyrighted material is a crime (in the US.) This docker image contains Apple copyrighted files, probably, but anyone feel free to explain if I’m wrong.

You need to prove commercial intent to profit

If a choir teacher distributes the lyrics to a Britney Spears song to their students for practice, there is nothing illegal about this

If a choir teacher starts a website britneylyrics.com and puts ads on the website, that would qualify

The EULA might prohibit redistribution, but you don't need to accept an EULA to copy-paste files, as far as I know.

I think you’re right for the definition of criminal infringement. I still think this image is civilly liable for infringing Apple’s copyright (not a crime as I originally said.)

> The EULA might prohibit redistribution

I don’t think it matters. Copyright law automatically forbids copying. Well, assuming Apple complied with any requirements to have a valid copyright, which seems a safe bet.

My understanding is that commercialization certainly weakens a fair use argument, but that its absence does not automatically make a reproduction and/or distribution fair use.

You don't need to accept an EULA to download the files from Apple either.

I suspect that it probably doesn't matter; Apple has generally not cared about Hackintoshes as long as you aren't selling pre-made Hackintoshes. Apple probably doesn't really mind for stuff like this, since this probably isn't realistically eating much into Apple's market.