I wanted a mummy Touhou, ZUN! 😭
Anyway, you reckon Nareko was also corrupted by the constant flow of garbage data into the pyramid? Like, she's right on the pipeline, and she's exposed to the raw data over the years. And the sphinx dream changed her at some point.
But then there is the question of why she didn't notice the sudden spike of the inflow. Why didn't that corrupt her more? 🤔 Perhaps by this point she had built an immunity?
And yeah, I don't think the 浄穢 part is supposed to be "Clean Impurity = Purifying." That phrase is literally "Purity and Impurity". So I believe it is part of the whole name, making it "Mount Asama Jōe."