Your first post claims it isn't a test of scholastic aptitude, and then this one says that it does predict scholastic success, and what could reliably predict scholastic success other than a test of scholastic aptitude?

Sure, a big donation by the student's dad, but that's a known quantity. I took the same SAT you did if it matters.

Which certain backgrounds are you referring to? I'd ask you for the references to show the supposed boost that test prep gives to SAT scores, but then I'd have to find the papers that fail to reproduce it...