(The Challenge is to prove the premise wrong by pointing to even one long-term, ongoing examination of open questions in math pedagogy, by any group of people, anywhere. The context is K-12 mathematics.)
Of course I do not discuss math pedagogy, for the simple reason that there is nothing to discuss. Or, so I believe.
I believe: (1) We know everything there is to know about school mathematics (i.e., K-12 math), and (2) We know everything there is to know about how to teach it.
So, the only really important question is why don't the schools do what we know they should do to most effectively teach math to the most students?
The answer can only be found by exploring the politics of education, not the mechanics of long division or anything like that. We know the mechanics of long division. What is less clear is why the schools don't teach it well, if at all.
If you believe otherwise, why do you never discuss issues of mathematical curriculum and pedagogy? To the contrary, you seem eternally consumed with issues of social justice and your petty, personal squabbles with, well, pretty much everyone in this forum.
By your words, you say one thing. By your actions, you seem to be in full accord with Haim's Challenge.