4chan/Kiwifarms lawsuit against OFCOM dismissed for lack of jurisdiction

No. Extradition generally can only occur over conduct that is criminal in both jurisdictions and speech in particular is protected in US extradition agreements.

As a legal matter, it's an open question. The purpose of the lawsuit is to get the courts to officially rule on this matter because it's far reaching implications for the future of free speech on the Internet.

As a practical matter though, it's completely unenforceable in the US.

Please don't post angry snarls at groups of people like this on HN. Yes I know, anyone can point to egregious things that happen on sites like that and assert that they deserve it. That's not the point. The guidelines make it clear we're trying for something better here, regardless of what happens on other sites. https://news.ycombinator.com/newsguidelines.html