You're so full of shit. Like the vast majority of Touhou fandom, I got sucked into the franchise and learned most of its world through its doujins. The characters' interactions in 90% of TH dj do not need any knowledge of canon to enjoy. Rocket fuel 21, Rireba, Banpai Akira, Millet Soup, Personal Color, Akatsuki Dou and so on and so forth. You sound completely clueless about the franchise.
That's what made TH so different from stuff like KanColle and LL and Hetalia etc., where you must have some canon knowledge to fully enjoy the characters' relationship and understand their dynamic. TH is the franchise that is built almost entirely upon fanon, where every single doujin have a different way to retell the vague canon stories. When you've read a couple dozens of TH dj, you automatically have a solid understanding of Gensokyo.
Case in point: I know many people who love reading LL doujins because muh lesbians, but none of them know exactly what schools there are in LL, what the plot is, what the goal of the girls is etc. Same with KanColle doujin-only fans, who don't know more than 3 ship classes because all they know is that there're various lesbian couples with cool designs. In contrast, any Touhou doujin-only readers will be able to tell you correctly what kind of world Touhou is, who are the master of who, what are the various factions in Gensokyou, etc.