Gating based on SAT is literally discrimination. It is also not fair, because those kids got lucky being born to the right parents. But just because it's discrimination and unfair, doesn't mean it's bad.

Other types of discrimination are bad because they create effects that make society worse overall (more sectarian or class-based tension, more corruption, less growth).

Taxpayers, exercising their own self-interest, should pick and choose the good types of discrimination to support. There is no need for morality here.

TLDR, I am in agreement with you, but I wanted to frame the argument in this way.