I don't have a good track record with mormons and one physically assualted me twice. Not one accepting mormon thus far.
And I don't ignore or discriminate against religions, this is more just on who I let myself get friendly or close with. If people identify with their religion it suggests a stronger faith and possibility of that faith influencing their thoughts on the LGBT community, so I don't ignore so much as tread cautiously until such a time, if at all where the possibility to explore friendship opens up, assuming there's anything to base that friendship on. Honestly, someone who identifies with their religion isn't always a great friend to have as an atheist. I really don't like discussing religion with friends. I don't care what someone believes, they can believe in the tooth fairy or Santa for all I care. But if someone identifies with their religion to the point where you know their religion before you actually know them, that's enough of a turn off for me anyway regardless of LGBT issues. So I guess for a double issue, as an atheist I'm out right there anyway.
Although to be honest, personally, and maybe this is the result of living in the UK, I wouldn't say I've experienced christians to be the #1 non-accepting group. I mean, yeah, we see douches like the Westboro church in media and so on but in personal, every day life, I haven't really experienced any problems with christians myself. I've had far worse problems from muslims. Was bullied a lot at school with tons of mean things said to myself as well as the out lesbians (I was in an all girls school). And I've had muslim doctors refused to treat me. And still I'd say more issues from mormons than any other type of christians.
I think the truth is that it's become okay to bash Christianity but not so PC to bash jews or muslims that can be just as bad or maybe even worse.