christianity in general starts with the assumption that a human is a sickly animal that needs to be rectified in all kinds of ways, so I can see how they in their indiscriminate pursuit of afflictions (as it were) included homosexuality in their list. To me it's obviously a cultural thing, indeed having roots in religion.
I think it might be an emulation problem too, especially in people that have a iq lower than 100, 90, 80... We learn through mimicry which is emulation and maybe they find it difficult to emulate sexual interests that are not native to themselves. Like the fact developing children can not emulate the visual perspective of others until the age of 5, maybe they too find it hard to abstract sexual interests that are not native to them. They have little imagination for stuff they can't experience, feel or think, that imagination leads them to rely on themselves as an axis for what is good and bad.
An analogy:
The low IQ bully says something, he assumes it to have one meaning. When the nerdy kid is confused because he understands there is a few inteprretations of what that statement meant. When the bully sees the nerd visibly confused he laughs, thinking the kid is silly, he doesn't understand how to
socialise. In actuality, the nerd only asked what he meant was because there was more than one interpetation, but the bully didn't know that. He thought there was only one meaning, because that's all he could think about.
Wittgenstein is on my mind a lot recently, so I'll paraphrase the first few lines of Tractatus Logico Philosophicus:
The world is all that is the case.
The world is the totality of facts, not of things.
The world is determined by the facts, and by their being all the facts.
The world, determined by the bully is all that he knows. with a low ability to learn he is reluctant to ideas that aren't intuitive to him. The bully judges the world by what he knows, and thus he determines for the world to be correct must be based on his subjective interpretation of the world. I am right, you are wrong.