Then you haven't seen the kids I'm talking about.
If there is a specific math-related disability, that's diagnosable and comes with varying degrees of modification, including not having to pass the test. Sometimes probably not even taking the test, in the case of, say, Down syndrome and serious head trauma.
I have dealt with 20-year-olds still barely fluent in single-digit addition, and often there were environmental/cultural factors (like never having attended school). I've seen others who understood some algebra concepts, but insisted they
could not learn multiplication tables. If they could add, I had them do that.
But if you are talking about non-disabled or at least non-diagnosed kids, IMO U.S. culture reinforces widespread math phobia, even among elementary teachers. When I hear a very bright person say, "I can't do fractions," I sometimes suspect they have a psychological block, rather than some native lack of ability.
If people can count, add single digits and recognize shapes, they
are doing math, and there's work available for their level. In case of severe disability, teachers generally don't want to torture students, but they do tend to encourage progress. Can you explain more specifically what you mean by "some kids can't do math"? You mean at
any level?
BTW education standards far predate the current "Common Core" hoopla - do you disapprove of them in general? A lot of teachers aren't wild about them, but until the last 20 years or so, except in a few states, there was no performance bar at all to graduate high school. If you accumulated the credits, you graduated. High-stakes tests are more a function of NCLB and before that a bipartisan standards movement. From what I've heard, states may have more flexibility now to drop that requirement. Not totally sure about this.