I don't really know why LGBT community are still discriminated in this day for fuck's sake.
You have thousands of years of religion and economics (not necessarily different things at times) saying procreate because we need more followers and workers, possibly coupled with a visceral dislike (though I am not sure what might cause that as far as nature vs nurture*) in many cases**, and changes that allow it to be ignored (infant mortality, production levels/mechanisms and even things like the pill) are still well within living memory and you still wonder why?
*various cultures have rather different approaches so more nurture than nature from where I sit. Equally we do have a wonderful dataset from those that would isolate their children from any depiction and you then get the innocent as you like question.
**I read something once that asexuality possibly had trouble being recognised because where fumbling matching genitals may not work for a given person it is at least a position they can comprehend in another, opting to not fumble at all being an alien concept as sex drive for many people is perhaps not all encompassing but certainly a very potent force. Not sure where that leaves the hurry up and choose thing that bisexuality seems to face at times, from various sides of the would be spectrum no less, but hey.