When you start storing stuff (ie., LJ posts) on servers in the US, you have digitally entered the US and what you place on those servers does have to conform to US law. While you aren't physically in the US and couldn't be arrested by US law enforcement, if you did this on a large enough scale, with child porn or identity theft, etc., it's likely an arrest warrant would be issued and depending on where you physically are, extradition might be sought to bring you into the US.

For blog posts, it's unlikely it would be large enough to interest law enforcement but 6A still TOSses you because the content is illegal. So US law is enforced on what you do, even tho you are not in the US. You can't insist that 6A keep your illegal content on your LJ because you're in some other country and when you signed up at LJ, you agreed to abide by the laws where 6A is located, not the laws where you are located. If you want a blog that allows content per the laws of your country, then you need to have it hosted by a service located in your country.

It's the same for me, I wouldn't expect to be able to host a website selling Nazi artifacts thru a French website - it's illegal there. It's not illegal here in the US but the French company would still TOS my website because the laws they must follow are French ones, not US ones.