Except that it's not just about Westerners full stop; there's also an element of exoticism, compounded by the lack of proper interactions with the West by most

Except that it's not just about Westerners full stop; there's also an element of exoticism, compounded by the lack of proper interactions with the West by most of Japan for around a century. Clearly these depictions of the West are done from a hugely emic point of view, with the distortions of the depictions of the West distorted partly by the art style but partly from the lack of accurate information. And yes, the concept of the Other is not easy to illustrate because it has less to do with the parties involved and more of their understanding of each other, the lenses through which these preconceptions are analysed still being debated to this day. It's helpful that there is a word, even if it's merely shorthand, to describe this concisely. There is nothing black and white about the Other but equally this being a story simple of Western and Japanese is not as night and day as you claim.