Just for your consideration:
I graduated high school, in CA, with one year of Algebra, then got an two year degree at a JC. I then switched majors to Engineering and found I was way underqualified for Freshman Calculus. I then took three semesters of Math (Advanced Algebra, Trig/Geo, and Pre Calculus). I then had four semesters of Calculus and differential equations), at the University level. Not all people who go back for lower level Math courses are 'boneheads'.
In my case, in HS, I simply went through the system w/o motivation or guidance to take courses that were not required, at least as far as Math was concerned.