I've found about half and half, atheist and Christian homosexuals. I believe the reason why you might have found so many homosexuals that are atheist is because of the sheer intolerance Christianity holds towards homosexuals. Do to the intolerance they receive, I believe they start questioning faith and thus realize there is no "God."

Though I've also found it having the opposite effect. I've had a homosexual friend who I bump into off an on for the last few years. He's been through a lot of bashing by Bible thumpers and for quite some time there, stood strong with me in my anti-Christian views and arguments. I have reconnected with my friend recently and now he is clinging the possibility of there being a "God" and making up his own rules about "God." He fixes the image in a way that pleases him, such as "God loves homosexuals, it's just the Christians have it wrong." I hope my friend finds the strength to find comfort in his own identity instead of hoping for support by the mystical sky daddy, but its his life.

@Stefan Orr: Actually Satanism is tolerant of homosexuals. That's one the biggest reasons I am one, the tolerance of various lifestyles. We Satanists don't practice blood sacrifice, hold animals and the Earth sacred contrary to popular beliefs. WE do however believe in pursuing what makes us happy so long as it isn't harming others :)

Much love for atheists and non-believers though, anything non-Christian I'm chill with.