Actually, this is a lot broader than that, but that was one of the places this post started. The other was Rana's comment on a different post, words to the effect that the fan-cultures in question seem to divide themselves based only on some very fuzzy Orientalism.
I agree that fuzzy Orientalism is the most regrettably common way Western fans of similar media from different national/ethnic groups (eg comics and manga) express their differentiation. That particular expression is generally a lot of hot air, yes.
But I also think there are real fan-culture differences, touching on though not always rising directly from the mother-culture differences of the sources. This is my attempt to articulate the ones that I've seen. Warning: generalizations ahead, though not baseless ones.
ETA: To elaborate, this post is based on my own and my circle's experiences in various fandoms; unfortunately I managed to phrase things rather more generally and universally than I quite realized at the time. *rueful* None of the following is actually meant to be a Declaration Of How Fandom Is Everywhere. That said, the experience in question is not a narrow one, and I think the following is representative of a significant section of manga (and anime) fandom participants.( Let's look at this. )
Now, what I would be interested to know is: do the same kinds of differences show up in the Western fandoms of Western and Asian TV? Or of Western bands and Asian bands? And do they manifest in gaming fandoms? That last especially interests me, since the game sources seem to be the most self-aware of the trans-Pacific trade.
ETA: As per suggestion, I would like to point out that I have not been present for the bulk of wrangler discussions on associated issues. These are thoughts going off in a different (somewhat) direction, so please to be not be bringing other fights in here. I am an unaligned polity.
ETA some more: Will not be replying to further comments on this one because work has descended for the term. Talk among yourselves if you like.