The point is though,
1) He didn't commit a crime in the UK. There was no law forbidding him to do these things. Rightly so? Maybe not. Does it matter? I wouldn't say so. People should get in trouble based on laws, and laws only. It's about the principle, if people can get in trouble for not breaking any laws, but you know, he's a bad dude and all, then there is a serious problem with the legal system.
2) He did this whilst in the UK, and is being extradited to the US. I read that most of the site's visitors weren't even american, I'm not sure about the accuracy of that but I don't think it matters. You shouldn't be extradited cause you did something that's illegal in another country. Are we going to start extraditing people to iran for blasphemy as well?