That's just a result of faggotry at large. If there's a niche thing, they will take it for themselves unimpeded, because there are few places where they will receive pushback. After all, they have top down support from the system. If a site kicks them off, they'll complain to the various hosts, then to any financial organizations, be it their bank or payment processor. Legally, you as a business owner can't deny them because they are quite literally a protected class in basically all Western countries. Way before that however, the issue is almost merely that most people are just going to take it and respect the system because they don't want to be uncomfortable. They're supposed to love faggots and niggers.

Lastly, Touhou is just a bullet hell series that started in the 90's. It's just a doll of a video game character. It's just a product. Buy it or don't. It's not by itself an endorsement of faggotry.