It absolutely is, at least for the kind of Christianity I adhered to. To be clear, I am of the opinion that "being a Christian" means actually holding at least some personal conviction that god is real and that the Bible is an inspired text. Once you are in the territory of such beliefs with the Bible clearly denouncing homosexuality and stressing the holiness of the man-woman relationship, not frowning upon homosexuality is just being inconsistent, it comes with the territory. My backwards ideas about homosexuality entirely depended on my belief in a Christian god. As such, as soon as my preference for a bigger picture than my existence on earth finally stopped being enough to patch all the holes, my ideas about homosexuality got revised very quickly and I am a gay-lover supreme nowadays.
Me being a Christian for so long cannot be excused, however, my adherence to Christian beliefs entirely excuses my ideas about homosexuality at the time. I have no idea how anyone is anti-homosexual from an atheist platform. All in all I am not sure what you really want from me here Heskey. Am I a bad person now, even though I have distanced myself extremely far from my prior beliefs in regards to both religion and homosexuality? Have you been a perfect little Bayesian all your life, immune to cognitive dissonance, that you can be so damning? In fact, you claim to have been a Christian and to have never doubted the correctness of homosexuality, that is a nice example of cognitive dissonance right there. Adjusting your religious beliefs to more easily fit with modern society.
By the way, I think the posts Leshma is referring to are in here, read it and weep. I said something really weird here, and I think even at the time I was a bit confused with what I meant when reading it back, and found myself agreeing with what Rhekimos posted next. It sounds pretty shitty though.
http://forum.melee.org/general-off-topic/gay-marriage-you'r-thoughts/75/