If you are a believer in an omnipotent Gawd, then the only gawd-like conclusion is that your Gawd made these people in his/her/its' image, it should be blasphemous to denigrate them.
If you are a real atheist, your attitude most likely is, "none of my business"
The only thing I can conclude is the haters are afraid they will somehow become infected with beliefs/life choices other than what they were taught, which is a sign of stupidity.

It's definitely learned. Homophobia and sexism are woven into our society so deeply we feel like its naturally occuring but the fact that societies that don't have those issues exist/have existed shows its not innate. Racism and zenophobia exist across societies so those are probably functions of our biology, though easily addressed by more open societies with a lot of exposure and education.

Sexuality is a spectrum no a binary system.

Religion has taught them this, ignorant people who do not understand science and medicine and some who are not sure of their own bodies.

I think people tend to believe what they're taught. If you're taught to be an intolerant and close minded bigot you'll be one and vice versa. Most people don't have the courage to reject their foundational beliefs and form their own belief/value system based on evidence they gather themselves.

I get irritated because I'm sick of hearing about it all - that's my aversion. Why do all the variables (can't be bothered getting all the LNBT'sS etc listed) insist they are interesting to others? They ca do their own thing - I don't need to know about it

Religion runes peoples lives. Im gay atheist and proud of it.

Aversion to non-cis, non-hetero sex is purely the result of cultural conditioning. Human sexuality is NOT primarily for procreation. Less than 1% of the 100 million or so sex acts estimated to occur daily are fertile. That’s a lot of biological energy to expend for something with such a low success rate. The other 99% of sex acts must be for something else, and indeed they are. The primary function of sexuality in humans is social bonding and pleasure. Reproduction is a side effect for a certain range of those on the spectrum of gender and affection. Tying sexuality to reproduction was a parsimonious way for evolution to kill two birds with one stone, but pretending they are exclusive is, well, unscientific at best.