I was under the impression that the whole japanese thing was tied to the fact that in the 80s/90s (i.e. the decades vaporware tends to parody/use as inspiration) japan started being seen as this analogue to the US in asia because of the economic bubble and business people were scrambling to learn japanese, and it was gonna be the country of the future, etc. i.e. I think it fits into the vaporware aesthetic not to exotify per se, but as a retrofuturistic parody/nostalgic callback to how americans viewed japan in those decades.

to make all of that a bit less convoluted heres a quote by an actual vaporware artist guilty of the issue at hand:

"情報デスクVIRTUAL, alias of Vektroid, describes her album 札幌コンテンポラリー as ... “a parody of American hypercontextualization of e-Asia circa 1995." via wikipedia