I always have mixed feelings when they go by. It would probably be an understatement to say I am not exactly fond of religion. On the other hand, it's hard to really be all that upset at people for promoting tolerance.
I think there is a parallel here to the Creationism-centric accomodationism/"New Atheist" debate. Namely, is a religion that accepts Leviticus as scripture compatible with a stance that is tolerant and accepting of homosexuality?
The Bible seems pretty unambiguous on this point, so I would tend to answer "no". And until a little over a year ago, I viewed attempts by LGBT people and their families to reconcile their religion with the reality of their lives to be rather superfluous. The whole philosophy is based on intolerance; why go to all the mental gymnastics to remake it into something tolerant when you could just discard the whole godforsaken thing?
The movie is heartbreaking, and helped me to understand just how important this issue is. Some families are simply not going to give up their beliefs no matter what. For them, finding a way to reconcile their faith with homosexuality is not just an exercise in academics, but rather it is critical to maintaining their familial ties. In some cases, it could even be a life-or-death issue, as the shockingly high suicide rate among LGBT teens demonstrates.
For the Bible Tells Me So puts forth some arguments addressing the passages in the Bible condemning homosexuality and how they can be interpreted in ways other than the obvious one. The most convincing was a reframing of the story of Soddom and Gomorah, which basically argued that the cities were destroyed because they failed to show proper hospitality to travelers, and that teh buttsex was just a red herring. I actually buy this one, but it still leaves numerous other passages that are pretty explicitly anti-gay.
To deal with Leviticus, they have a rabbi who argues that the word "abomination" is not a particularly good translation, and that the original Hebrew word would have been close to "against tradition" -- so therefore, Leviticus was not saying that homosexuality was evil, it was merely saying that the Jews in the time of Moses just traditionally didn't do it. This sounds compelling until you remember that the penalty proscribed in Leviticus is nothing short of death, which makes it a bit hard to swallow that this was just intended as a style issue. (And anyway, the historicity of the story of Moses is extremely dubious, which it makes it sort of meaningless to talk about the "cultural context" of a culture that was made-up...)
Other mentions of homosexuality in the Bible are similarly framed as an issue of "this is our culture" as opposed to "this is what is right and wrong". To me, it's a bit ho-hum -- but if it means the difference between a family loving their son or daughter and embracing them for who they are, vs. estrangement and resentment.... Hey, I'm all for it.
So I roll my eyes a bit when the churchies march past in the Pride parade. But I'm glad they are there, anyway. It's progress.