I often tutor my friends kids in different levels of math. They usually come to me after struggling with something for a couple of weeks. The first question I ask them is for them to explain to me how their teacher explains how to do it. The reason they are struggling becomes quite clear in seconds. There seems to be a conspiracy even from the youngest ages (watch a 9 year old do multiplication and division, for a “wow, really?” moment) all the way through high school algebra to make sure the steps to do anything are as numerous and confusing as possible. I also tutor university level kids, and they seem to struggle in calculus because of what they didn’t learn in school.
Bingo. It’s not the standards, it’s the teaching method - unfocused, lacking rigor, and overly busy. They should call it deconstructed math. That’s about the most charitable label.