The reason why math is 'hard' is the same reason 'exercise' is hard. It takes a combination of skill and practice (a/k/a discipline) to make it 'easy'. And in a similar way to the endless "how to lose weight" fads, we see "how to do make math easy," when <easy> is not 'in their nature'.
The main problem with math education is that it is falsifiable. Math teachers can be measured, because math performance can be measured. This is why it makes educators nervous. And, I suspect, why they mostly suck at teaching it. They are the ultimate risk-averse sub-population. Subconsciously, 'educators' <hate> the idea of accountability, because it is predicated on the notion of potential failure. But the 'educational' establishement is <built> on the foundation of unquestionable <authority>. so math is for these guys an existential threat.
TLDR: To be good at teaching math, you have to be open to measuring your failure, which makes people feel bad. Including the teachers.