The LA Times agrees that AP credits are useful for predicting success

Since we're quoting the L.A Times, it goes on to say:

But AP students who take the courses but don't take the exams, or score poorly, fare no better in college than non-AP students. Yet UC continues to give them the grade boost.

Hm. Apparently merely appearing in the class gets you the extra consideration.

None the less, it is not in any sense aristocratic beyond various jealous minds.

No one says it's aristocratic (quite the opposite, in fact).

The report further notes that despite attempts to bring more AP courses to all high schools, middle-class students still have far more access to these advanced classes.

What it is, is an unfair advantage to already advantaged students.