They also force ISPs to block IPs [0].
I feel trying to say that's not "blocking websites" is playing games with words, and the results are functionally the same to the "average" user.
The fact that the US effectively claim juristiction over the root DNS system is a more a geopolitical power thing rather than a legal restriction.
[0] https://torrentfreak.com/us-court-orders-every-isp-in-the-un...
Ofcourse, everybody ( well, outside the UK ) are OK if UK orders UK ISPs blocks sites for their customers.
Another advantage as the other reply has mentioned is that courts have broad authority but must narrow the effect of their rulings to the minimum necessary to address the suit. In this case it would certainly lead to 4Chan being blocked by UK ISPs by order of a UK court. I think even 4Chan would be fine with that.
This is different than 4chan allowing UK viewers to access the website at all.
Country A has a law that says X is illegal, and tries to enforce it against companies in country B where X is legal.
Whether either case is reasonable is a different question, though.
The US by and large doesn't censor websites even if the content is illegal in the US. They'll get a warrant and seize servers or domains if it's in the country, or maybe poke international law enforcement for cooperation, but it doesn't really extend beyond that.
https://arstechnica.com/tech-policy/2022/05/judge-rules-ever...