I get it now...

What these meaningless glowie attacks are about. I was just not seeing the perspective: We already know this from Touhou games, it's exactly like the yokais said; they're there for training, they're for target practice and removal of karma. They represent karma which must be cleared.

Wave after wave of small fry will attack you, and they won't stop, they can't be argued with and they have no self preservation instinct. They're like insects or viruses, and that's all they are. We need to have this perspective, that's the yokai path. Clear all of them and there will be a boss, then that level is finished.