[hi19hi19]

Usually doujin music is used as a classification, not the actual genre.
It's akin to calling a something "indie" music, not really a genre in itself.

You can have a doujin rock song, where rock is the genre.

Using Touhou as a genre is a little weird, because we wouldn't just label say BB Evolution with the genre "Final Fantasy"
On the other hand there are SO MANY Touhou remixes that it's kinda taken on a life of its own as a subset of music. idk