I'm admittedly working from a small sample size, but I know of at least one religious school that refused to teach any math that involved graphing on an x/y/z axis because satan. I think they were actually mad about Rene Descartes, but a huge part of geometry/algebra took the hit. Or rather, the kids' education did.
"We begged them to teach us this because we all knew it was on the SAT exams, but they refused."
It was a shame. I spent a pleasant evening going over some of the basics with a guy who graduated from that school - including the basics of calculus - and he seemed to pick it up pretty quickly. We weren't solving problems, obviously, and it was 15 years too late for the SAT but we covered "here's what it is and here is how it can be used in problems."
Even sadder - I have a nephew who wanted to become a scientist when he grew up. It wasn't some little kid thing either. He had an enduring interest in the topic and he was a clever kid. That was never going to happen because at some point he would have needed to go to a school that taught math and science. His school did not, and secular colleges were not going to be much of an option for him since he would need to leave the safety of their insular world.
He's a baby Nazi now, and seems to be dabbling in incelism.