These things are always all over the place. Don't we have some feature to hide titles which contain "touhou" in their name? As there is no "touhou doujinshi" tag, I don't know how to block them. They are of all genres, kinds and colors.
If Touhou gets a tag, I would say ALL doujinshi of any fandom in existence needs one then. I mean, everyone has different tastes. Or just get used to skipping over any obvious fandom titled works you hate the fandom of.
