Do you have any links to info/evidence about that?
I see where colleges ask for SAT/ACT scores, and SAT 2 scores, but not AP scores. I don’t seem them mentioned on the Common Data Set. I think the issue is that not every student has access to the same amount of AP classes so it is hard to use it as input to admissions.
If you think about it, an AP test score says “can you get college credit for this?” If you don’t get a high score, then you need to take the course in college…which is the point of college.
For example, Stanford says:
Students currently enrolled in AP courses are not required to submit AP scores as part of our admission process. AP scores that are reported are acknowledged but rarely play a significant role in the evaluation of an application. Grades earned over the course of a term, or a year, and evaluations from instructors who can comment on classroom engagement provide us with the most detailed insight into a student’s readiness for the academic rigors of Stanford.
http://admission.stanford.edu/basics/selection/prepare.html