Teaching it in the classrooms is tricky because what people really mean is “how” to teach it in the classrooms or at what age so that when the kids come home and speak about it openly in mixed company (as they usually do) it doesn’t make everyone uncomfortable (which is the real problem), many people are just uncomfortable with it. Not dissimilar to having your daughter happily demonstrating how she learned how to use a condom utilizing the candle during family dinner. This would make most fathers uncomfortable at any age but knowledge should never be withheld.
You referred to it as unnatural inferring that it goes against nature. But in actuality if humans did not have any bi or homosexuals we would be unnatural by definition because over 1,500 other species exhibit "same sex" behaviour. One of the most fascinating to me are the species of Black Swans where two homosexual males may team up and befriend a pregnant female forming a threesome and then when the eggs are laid the female is sent packing and the males raise the family.
I dont agree with you that people feel it is disgusting, I think they are just uncomfortable because they lack information and education on the subject like yourself. If left untreated this can manifest itself into embarrassment, anxiousness, anger or rage.
