>They are stating that companies operating in the UK and providing services to UK individuals

did you mean to say "companies operating in the UK and(including) companies providing services to the UK"? because the way you wrote it, it would not apply to 4chan

and what is not being mentioned by most commenters is, if the law is unenforceable on a US corp, what is the chance that an individual associated with 4chan Inc could find themselves individually arrested were they to set foot in a Commonwealth country or somesuch

I would expect the US not to ignore such an arrest so its really a question if going after 4chan this way is worth causing a diplomatic incident.