I looked up the definition of asexual, just to make sure I was clear on it, and here's what I found:
1. Sexually inactive: without sexual desire or activity. - Obliviously, this is what you are referring to in your post.
2. Without sex-linked features: lacking any apparent sex or sex organs.
3. Without sexual fusion: describes reproduction in which there is no fusion of male and female sex gametes, e.g. vegetative reproduction or budding.
I was thinking in the context of the latter two, but that being said, I still am not very fond of using the term asexual to refer to a person. To be honest, I find it a bit offensive. I fall under that first definition, and if someone were to call me asexual because if my lack if interest in pursuing a relationship, I would be angry, because I find the term dehumanizing. But that's just my opinion.
I sincerely apologize if I offended you. I had no motive other than to analyze a fictional character and his behavior using established psychological / psychosexual terminology, and attempt to provide an explanation as to why the term "asexual" is often applied to him.
In general defense of people who do describe Sasuke as asexual, I think most of it has to do with his role in the story. While other characters could conceivably be described as asexual as well -- Gaara or Shino, for example, since they have never been characterized as having an interest in sex or romantic relationships, per se -- they do not play a part in the main relationship dynamic, nor are they the direct romantic rival of the hero.
Much has been made out of Sasuke being the focus of romantic attention and relationship aspirations. Sakura, Ino, Karin -- even Mei commented on what a shame it was to kill someone so handsome, and that she would do so with a kiss of death, so to speak. Sasuke's role is one with a significant sexual theme and purpose -- at least as sexual as one can get in a shonen manga.
Yet despite all the attention and opportunities, Sasuke never reacts in a sexual way. That's what highlights his behavior as seemingly asexual. Strictly from what we're shown, he is "sexually inactive: without sexual desire or activity." It's all the more glaring because he's supposed to be some sort of great eye / arm / bed candy to all the girls.
And really, even if Sasuke later entered into a romantic relationship that would not mean he isn't asexual. Asexuals have relationships for a variety of reasons including the desire for emotional intimacy, marriage, and children.
Again, sorry if I offended anyone.
Edited by KnS, 23 October 2013 - 08:14 PM.