What happens if the church doesn't go all homophobic?
Does a gay identity evolve sooner?
Absolutely not. The 'gay' identity developed because governments banned sodomitic practices, and actually spent significant resources trying to wipe them out. This pushed the proto-gays underground, and instilled within them a sense of solidarity. This sense of solidarity coalesced into a subculture, which in turn led to the point we have today, where huge swathes of the population chose to define themselves primarily on their sexual preference.
People really need to get into their heads that there is nothing universal about 'homosexuality', (or 'heterosexuality' for that matter), the invention of the two terms as opposing concepts arised only a couple of centuries ago. Indeed, I'd argue that it was the concept of heterosexuality that arised first, as a code of state-sanctioned sexual 'normalness'. 'State-sanctioned' being an important point, pretty much as soon as governments had police forces advanced enough to poke their noses into peoples' bedrooms, they did so - early modern governments were obsessed with social engineering, and reinventing human sexuality was principle in such projects.[1]
I don't view the discovery of the 'Gay identity' as any kind of enlightenment. I view it as an understandable backlash against a legacy of sexual authoritarianism. And, I predict, as future sexual historians from a time where society truly no longer cares what people get up to in their bedrooms look back on our period, they'll wonder what exactly the point of dividing the vastly diverse field of human sexuality into two mutually-exclusive opposing parts was.
[1] Such projects were not confined for metropolitan populaces, the crusade to correct sexuality was central to the Colonial process. As an aside, I'd strongly suggest that the reason why many developing countries today seem so backward on issues of gender and sexuality is because their own concepts where so completely fucked up by well-meaning Imperialists. White peoples spread across the globe, covering up tits, confining women to the kitchen and spreading religions that strongly restricted acceptable sexual practices. Imagine what would happen to our culture if an alien force turned up and told us what we thought was a 'man' wasn't a man, and what we thought was a 'heterosexual' wasn't a heterosexual. It would fuck us up.