I think everyone has some kind of sexual desire, however small, and that there are reasons behind asexuality. Like some people who are asexual because they find even the thought of it disgusting and would never want to do that have had some kind of experience that caused them to think this way. Some are like it because they are extremely introverted and can't even stand much social interaction, and don't want to be close to anyone in any sort of way, and therefore ignore any kind of desire until it is non-existent. For myself, I would say I am only asexual because I can never imagine myself doing anything like that, and it makes me cringe, as well as the whole introverted antisocial stuff, so it's kind of conditioned me not to have any desire. And there is an underlying problem which I won't go into details about, but Nicole, you already know half the story.
But I do agree that it is extremely annoying when people act obsessed with it, or that's all they can talk about. The jokes I can tolerate, or else it wouldn't be fair to dish them out.