AFAIK the whole doujin scene is all about "go on, violate our copyrights but don't complain when people violate yours".
ZUN's blanket ban on commercial distribution makes it really difficult and expensive to legally obtain anything when the only distribution channels are specialized doujin stores -- it's still commercial, but the ones getting the profits are various middlemen and not the arrangers and performers.
Zun actually does have a semi-formal license/terms of use (it primarily bans commercial use but also quite a bit of other stuff, much of which I think goes ignored): http://touhou.wikia.com/wiki/Touhou_Wiki:Copyrights https://www.animenewsnetwork.com/news/2011-02-14/tohou-proje...