Have you read through common core? That crap is confusing.
For example, in Grade 7, there are about 50 requirements, one of which is “Use proportional relationships to solve multistep ratio and percent problems. Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.” That sounds like an appropriate thing to learn in 7th grade.
Edit: In fact, most of the time when I am reading the standard I just nod and think “yep, that’s probably about when I learned that concept” when I grew up in California, although in a few cases (e.g. using scatterplots and proving Pythagorean theorem in 8th grade) I don’t think I learned them until high school.
As far as I can see common core defines standards of ability, rather than teaching methods. There are a bunch of awful, dreadful textbooks that claim 'common core compatibility' but which ignorant people conflate with being part of a common core syllabus, as if they are approved/endorsed by the same people who drafted the Common Core standards, whereas in reality textbook approval seems to be a an extremely politicized and corrupt process carried out by the individual states. I wish there were a single federalized syllabus, because it's not like Math works one way in Connecticut or Rhode Island and another in Texas or Arkansas.
Your argument is like saying Windows is terrible because you can find some poorly-programmed Windows software. Flaws in an individual textbook or exam paper are not the same thing as flaws in the standard they claim to adhere to. Perhaps you would like to use the link to the common core standard in the grandparent post to point out examples of what you are talking about.
So we can replace 50 extremely politicized and corrupt processes with one massive, impenetrable, extremely politicized, and corrupt process?
Otherwise, I agree. The problems are with implementation, not the standards themselves.