They know what it means. It means a copyright holder of the Linux kernel would have to sue them in China. Good luck with that.
It doesn't help that the GPL is not an easy document to read by the way :-/
It's also just basic common courtesy IMO to assume someone made an honest mistake even when you suspect they didn't (because sometimes your suspicions are incorrect).
If you can’t go after them, going after their customers would kill their business.
But this approach seems too cute to be feasible even on the long shot that the GPL would allow it.
If you don’t agree to The gpl normal copyright law applies and you can’t copy the program outside of fair use in your jurisdiction
In the early days of internet pirate sites there existed an argument that it was only the people distributing that could get sued for infringement. Similar when streaming happened it was argued that no copy was downloaded, and the users clearly did no distributing. With cable decoders (in countries without anti-drm) it was similar argued that no distribution occurred by the users or the producers of the cards.
Since then a lot of court cases has happened and as far as I know neither of those arguments have held up. There is usually a law or two that get digged up in order to have something to charge people with, and law makers has been quite diligent in address those kind of arguments in new laws.
But there is one major caviat. Those cases has all been by large media owners with both large teams of lawyers and "close" relationships with the legal and political system. A lone developer will have a much more difficult time.