Ah... That's just one troll. Some people even say he's a disillusioned Christian. Although personally..? I just plain don't know. Plus I don't really care enough to try to find out, either. :)
Anyway, though... With all due respect, I very much disagree with you on this. Can you find sex obsessed atheists? Well, absolutely, yes. Just like you can also find a few Christians who don't really care about other people's sex lives one bit. But generally speaking, though..? It tends to work this way:
Secular people, or people who follow religious/spiritual paths that don't really concern themselves with sexually related dogma, and other people's sex lives: "Other people can just do whatever... Meh. It's none of my business, anyway."
Most Christians, who follow a religion that's got TONS of yucky, oppressive dogma as it pertains to sex and people's sexualities: "Holy crap... My neighbors are doing WHAT in bed?! That's gross! Ewwww!!! And.. what are YOU doing in bed? If you're in THIS sort of relationship, what exactly does THAT say about your sex life? I want to know... I want to know ALL about it!! So that I can subsequently judge you, and condemn you for it!"
Just my experience, for what it's worth. (Although like I said..? This does not apply to EVERYONE, obviously.)