I'll offer the short version (and note that it isn't just EDM, it's also EnVision Math, too).
1. Unsound pedagogy doesn't really "teach" mathematical concepts or algorithms using "this is why this works" as an approach to numeracy...
2. Teaches partly through "algorithm discovery" process-- which is just as goofy as it sounds.
3. As if that weren't bad enough, it also teaches "tricks" to problem solving particular types of problems. Not particular methods which are universally applicable (say, that addition is "commutative" for example).
4. "Oversimplifies" (really, teaches them sloppily and incorrectly) many concepts that probably have no business even BEING taught within the context of the grade level in question.
I could go on and on, but won't.
