The first golden rule in these programs is never go after nor accept any student that is not qualified for the program. This does not benefit anyone. It doesn't benefit the student because they will ultimately fail. It doesn't benefit the department because they lose a slot for the student and the time investment. It doesn't benefit the school because it harms its reputation. Within the program that I worked, the idea that we had lax or easier admissions criteria for underrepresented students is categorically false and I mean this is the strongest possible sense.
Alright, so what did the program provide? A variety of things, but largely a support system for students who did not have peers from the same cultural background, which is important when you move away from your support system. It also provided resources for us to recruit at conferences, schools, and events that were overlooked by the departments themselves. Finally, it provided money to the departments assist in the cost of the tuition waivers for the students.
And, look, these programs are not perfect. However, let me be extremely clear, any notion that these students were not qualified and somehow tarnished the brand of the university are false. They were and are good and have been an asset to the university as well as their employers after graduation.
At this point, you should define "qualified". When affirmative action programs start accepting scores that are much lower than for other races, it begins to really call into question your argument.
Might want to call into question your own argument since college admissions aren't based on a simple ranking of the highest scores. Wonder why diveristy programs get questioned but not legacy or athletic admissions.
The problem exists, if there's a monetary incentive or even bonus for quantity (and diversity implies to quantify) over quality.
Edit: Removed a line that could have been interpreted as unnecessary accusatory.
This is a well known problem, written and talked about extensively by black intellectuals who came up before such programs were in place and had to mentor the generation that came up after.