Right now there are laws in Utah, Texas, and Mississippi that require you to identify yourself by government-issued ID just to post on social media. These laws are blatantly unconstitutional and currently undergoing legal challenges in court. That unconstitutional laws exist at any particular time or place has no bearing on whether or not they are unconstitutional, nor does the Supreme Court's denial to hear a case as they only take so many cases every year, and that particular one may not have been suitable for review for any number of reasons. Since you just posted the ACLU's press release rather than actual court documents I can't really say one way or another.
In any event, under the SPEECH Act, foreign defamation judgements are generally unenforceable unless they offer at least as much protection as afforded to citizens of the United States under our own laws. That law was passed in direct response to libel tourism. Censors looking to launder their censorship through the UK are effectively thwarted by the SPEECH Act, hence why it was raised in their filing.