I don't know the reasons for the lack of diversity in college education. What I can say for sure is that diversity at the university level is good for society as a whole. No one want to live in a society that is bifurcated by race and ethnicity. We need all people to go to college.
Yes, diversity is still a factor in university admissions because college campuses want their institution to be racially diverse. If students have nearly identical credentials but one is a white and the other is a minority, it is likely that the minority student will receive an admission offer over the other student.
Yes, diversity is still a factor in university relations, because a lot of universities, such as the University of Michigan are blatant about the fact that they use race in admissions. In fact, they fought a Michigan law passed by referendum that said that universities could not use race in admissions.
I have my doubts diversity is still a factor in university admissions. I have to assume that some universities may have a problem but that is probably representative of the people in charge. I have attended three different colleges and all of the seemed to be very diverse by nature.