It has always bothered me --- considerably --- that people who are math-phobic (let's face it and say
they don't understand math) are allowed to teach it. I mean, it's one thing to not understand vectors in three dimensions, but basic stuff like percentiles? Imagine hiring a skating or gymnastics teacher who had never done a one-foot glide or a cartwheel. It wouldn't happen. It's appalling.
Along the lines of IQ and executive function, I remember a meeting with a math teacher who didn't understand how I could claim that my grade-skipped daughter was "so smart" (I never used that term; it was her phrase), when she would forget to bring her book to class or have a messy backpack.
I said, "Oh, that's a difference in the development of executive function and cognitive ability," and gave a basic explanation. She listened, and then said, "I still don't believe it." That was in October, and it was a year that scarred both my kids.
I think that some people don't get it and don't want to. When you encounter one of them, I'm not sure there's much that can be done apart from a tactic of avoidance wherever possible.
