Q:  Why is it difficult for people to understand asexuality as a genuine personal preference? Of course, I am not asking how sexual education ought to be done, per se, but I’m asking what are obstacles to the process of learning about and understanding asexuality?

I think the biggest issue is that asexuality is rarely even presented as a possibility.  Interest in sex is presented as biological destiny.  You WILL want it.  You will even NEED it.  That’s just how it is.  You’re supposed to want it with someone who has compatible gametes, because that’s the way evolution ensured that our species will survive.  Even if you prefer someone with the same bits, well, you’re still going to have the drive, because that’s Human Nature™. And everyone hears that story from when they were born.  “Humans need sex to survive!”  And for most people, it comes true!  They reach a certain age and, wouldya look at that?  That sex thing is mighty interesting!  And she looks like a mighty interesting person to try it out with! And so the story is reinforced:  They told me everyone will want sex, then I wanted sex, therefore everyone will want sex. And then, along comes an asexual.  We don’t fit that pattern.  We don’t make sense in that story.  We weren’t part of what they were told about.  So, they try to make sense of us. We’re not old enough yet:  “You know, I never felt that way about a girl until I was older.  Give it time.” We just haven’t met the right person:  “I wasn’t interested either, until Sally changed my mind.” We’re afraid:  “Yeah, it’s scary, but once you try it, it’s not so bad.” There’s something wrong with us:  “You should want it like I do, so your hormones must be off.” And so on… They try to fit our experience to what they know, but what they know doesn’t include who we are.  They’ve never encountered the possibility of someone who’s naturally disinterested, so they assume that there must be something blocking that interest, something that can be fixed.  Even people who are asexual and simply aren’t aware of the term end up thinking along these same lines, because the story is so prevalent.   I think that the best path to understanding is to simply get the concept out there.  It’ll start to gain greater awareness, and the story will change from “You WILL want sex” to “You’ll probably want sex, but it’s fine if you don’t”.  Then, when an asexual comes along, instead of being treated as a challenge to the True And Accepted Order Of All Things™, the response will be “Okay, got it.”