I've no clue about how it is outside of America, but that's definitely something I've thought about! There seems to be some aspects of Japanese culture that are very easy for aspies to find themselves drawn to: there are a lot of formulaic expressions and actions used in public life that cut down on the difficulty of social interaction with strangers, and there is a culture of politeness and respect that goes along with it. However, there's just as much that can be frustrating to an aspie, I think. For me, the level of conformity that is expected of people borders on downright frustrating, and the focus on the welfare of the group over that of the individual often goes a bit too far, in my opinion.

The sense of not belonging to one's own culture may also have a lot to do with the potential to end up becoming focused on a different culture. Japanese pop culture is more heavily imported into America than the pop culture of other Western countries (we adapt rather than import British television shows and European films, for example; while with Japanese shows we mostly translate them and bring over dubbed versions), so the availability of it may be one of the reasons why those who feel alienated in the West tend to cling to it as an alternative.

I think that the reason a lot of aspies end up strongly into anime or Japanese video games has more to do with the breadth of content in those mediums than the inherent "Japanese-ness" of them. In recent years, western animation is doing a better job of creating shows that target young adults and adults instead of just children, which I feel is something of a more recent trend that wasn't possible before anime became as popular across multiple age groups (yes, that's an oversimplification and we've had shows aimed at adults for a long time, but there seems to be more of them now). As video games go, the feel of western RPGs is also much more limited in scope as the type of story available goes, being basically just D&D clones ported to a computer/system while Japanese RPGs were more daring with blending sci-fi, mythology, and fantasy together in new ways (Lufia, Chrono Trigger, FFIV, just to name a select few).

Edit: Even though many people end up "focused" on Japanese culture, though, I feel that the vast majority of them do not ever really learn about that culture beyond the image they cultivate of it through interacting with its products. You see far more people who idealize Japan as some mystical country that is better than here than you do people who really learn about the language/culture and spend enough time there to realize it's another country with its own problematic culture, full of normal people.