First of all.  We're talking about elementary students being taught by elementary teachers.   Sorry to say but this means predominantly female teachers.  This also means even if they are men they were not STEM students at university.   Most likely liberal arts who hated math and haven't taken it since grade 10.

"Math is hard".

"I'm not good at math either"

"You don't need to know math,  look at me"!

The problem is the teachers.  The same bunnies that wanna kick Sir John A. in the stones.