Actually - no, it can't. American law (and this site is hosted in the US) makes it clear that the content publisher is not liable for what's posted.
Sorry, thats wrong, dangerously so.
Liable law (and all other laws such as racism) can be applied in any country where that content can be accessed. This is why the UK is the liable capital of the world, every nationality of he world goes there because the laws are biased against the defendant. The only requirement is that anyone from the UK can access the content, in one case only six people viewed an obscure story in the Uk and UK law was deemed applicable.
The content provider is only un-liable if anything suspect is immediately removed and they can show that it was policed.
The US authorities will apply EU law automatically in criminal cases, US laws such as 'freedom of speech' don't apply to EU. Although I liable isn't a crime, so extradition doesn't probably doesn't apply, but fines and seizing of assets will do.
Bottom line is its probably better to be careful, I don't know if the site owner has EU assets,