Because entrance exam scores and grades are not anything like objective measures of a person's intelligence, wisdom, courage, grit, or even ability to do well in college.

What they primarily telegraph is their parents' income level.

There is no such thing as an objective measure of a human being.

So we take other things into account. Things that might account for why this grade or that test score are lower than somebody else's -- if this person had grown up in an affluent neighbourhood, they may well have scored higher than that person, not lower.

And because institutes of higher education think there might be more to education, and indeed more to being an institute of higher education, than pushing through wave after wave of high-exam-scoring cookie-cutter clones. There might be something, they may foolishly think, to having people from all walks of life and all socio-economic levels and all race/ethnicities rubbing elbows with one another.

Because although it hurts to say it, we are not a color-blind society. We are not a meritocracy. And until we are (and we may never be), then we have to sometimes make up for the fact that merit (whatever that means) is masked by other factors. Such as what part of town you grew up in, and how much money your daddy makes.