It's context. In the west, we are immersed in the context of Christianity whether we are Christian or not, whereas Shinto, if we're aware of it at all, is mainly some foreign fairy tale stuff we may know mainly from anime like Inuyasha. When it comes to supernatural beings in Shinto, "demon" is just a western translation, and since Shinto is very different from Christianity, it's not really an exact translation.
It's context. In the west, we are immersed in the context of Christianity whether we are Christian or not, whereas Shinto, if we're aware of it at all, is mainly some foreign fairy tale stuff we may know mainly from anime like Inuyasha. When it comes to supernatural beings in Shinto, "demon" is just a western translation, and since Shinto is very different from Christianity, it's not really an exact translation.