The way I see it, Japan is an Asian country, and fascination with Asian countries has a long history[0]. The other thing is that Japan has a vivid pop culture since WW2 and really ramped up its soft power effort, of which a significant aspect is the export of the Japanese culture in general [1].

The phenomenon OP is talking about is excellently captured in the "Thing, Japan" meme as well [2].

[0] https://en.wikipedia.org/wiki/Orientalism

[1] https://en.wikipedia.org/wiki/Cool_Japan

[2] https://knowyourmeme.com/memes/thing-japan