Demonic possession? What in the fuck are you talking about?
People are certainly open about being bigots under the guise that homosexuality is a choice.
If homosexuality is a biological construct, then discriminating against it is akin to discrimination based on race and you share a mindset with Bull Connor.
Own it.
Actually, there was poll (taken in 2000) that asked whether or not one's opinion would change if sexual orientation was proven not to be a choice. 75% said "no."
Now, polls are not always very reliable (especially when there is only
one... which was taken 12 years ago), but keep in mind that racism and sexism have existed and still exists despite the fact both gender and skin color are determined by genetics.
People will continue to promote hate whether science backs them or not. However, as of right now, some of them are (yes) hiding behind the lack of conclusive proof that supports sexual orientation is determined before birth. I can assure you, though, that their position wouldn't change even if there
was conclusive proof.