I don't really like the implication that everyone who likes a certain Touhou character is automatically Satan. Yeah, the loli overtones are a thing to be aware of, but I don't think finding a character who looks young to be visually appealing immediately makes you a closet pedophile.
Agreed. I looked into this fandom after hearing a lot about it and wanting to know why it was so popular, and here's a brief overview of the different spheres of fandom in regards to the art:
The meme artists: Generally the sanest of the bunch. Mostly cutesy stuff referencing Touhou injokes and memes (like the yukkuri bit), these artist tend to just enjoy the cutesy art and humor of the "lore"
Typically found: A lot of these on Deviantart, even has shown up in the Daily Life With Monster Girl manga and anime (the creator is a Touhou fan)
The porn artists: Depends. It runs the gamut of the adult characters to the loli shit, with one end of the scale being typical R34 nonsense, and the other extreme being sick fucks I wouldn't trust around kids.
Typically found: Look up Touhou hentai doujinshi on Google, not hard to find at all.
The crossover artists: For some weird reason, Touhou art and characters are used in a lot of crossover art, with some being odd yet amusing, typically tends to be used to spoof or parody whatever the crossover is.
Typically found: Image boards for the most part.