I am not a powerlifter, so disclaimer: this is almost totally an outsider's perspective. The powerlifting squat is low-bar (right?), which, to me, seems like it will necessarily make you use your back/hinge a bit more. The bar being lower on your back seems to mean to me that when you go to squat, you must hinge more, or else you would fall backward. It's just perplexing to me that people will load up that position and then wonder why it becomes the proverbial "squat-morning."
I'm not saying it's wrong or anything to lift that way; I get that PL has its own techniques for its own reasons. I guess it just seems weird to put yourself in a position that sort of demands a certain kind of movement, and then wonder why you have that movement. Am I just off-base here?