I'm aware of ZUN's "answer" from AWA, but...
How could the Moriya Shrine possibly not have gotten involved in Hopeless Masquerade?!
I just can't think of any explanation that doesn't leave their inaction seeming like something out of a bad fanfiction. They couldn't have just stopped caring about getting faith when it would be easiest to do, and even if they knew it was actually an incident that'd just be more reason to send Sanae, not less. Any speculation from previous games/SoPM/fanwank would be much appreciated.
Don`t know if its canon and if you read it, thus
spoiler alert?In Touhou Ibarakasen, it is mentioned that Sanae didn`t notice that there was a war going on.
Reimu had noticed because her ?stick? (forget English name) reacted to something (Kokoro?) but Sanae`s did not. (Maybe due to spiritual power differences)
Kanako tells her after HM was solved that she did notice to Kanako, but meddling in incidents (the war was just a incident to her) isn`t their job so they stood out. (They usually cause it, not solve it, lol)
She also said that she believed that sort of action wouldn`t increase faith/followers, and would rather fight other Shinto sects than other religions, speaking of which, (in?)famous Reimu already joined as a Shinto candidate in the war.
Moriya Shrine in Ibarakasen tries to increase faith by other means (use of technology).