1. I don't think that minorities are underqualified. It is an indesputible fact. Not all minorities are underqualified but the entire purpose of AA is to accept underqualified minorities. If underqualified applicants weren't accepted under AA then it wouldn't exist.
2. Higher grades and MCATs may not make a better doctor, but they are the best means available to choose between applicants. Your 'argument' is often brought up but is beyond weak. Grades and test scores are the primary factors used in admissions of URM's under AA too, the only difference is that you aren't required to compete against the entire applicant pool. You compete amongst yourselves and the URMs with the best grades and score as accepted.
The other side of your argument, poverty, is also weak because poor white people are discriminated against in favor of weathy minorities.
3. I somewhat agree with number three. Primary education is often poor and disproportionately affects minorities, but AA isn't given to nonURMs from bad schools, it is totally race based.
You also say 'in this country' which brings up two points: 1) african and black education was behind long before the US came into being, it's not as if blacks were educated pre-slavery but held back afterward, and 2) URMs (many black and especially hispanic) weren't even discriminated against in the US. A black or hispanic immigrant will get a racist preference in medical school admissions. What the heck!
4. I'm well aware of this country's history and of the reality that not everything is equal. You make things equal by having one standard and accepting those who best meet that standard regardless of race, not by discriminating against some to the benefit of others.
What you choose to ignore is that it IS history. You were never slaves and we were never slave owners. There is no genetic transmission of education. It is certainly an advantage to have educated parents, but I think it is even more important to have parents that prioritize your education. A motivated population will become educated in a single generation. Just look at recent immigrants. Immigrant parents (of any race including black immigrants) are more likely to have educated children than American-born blacks. It's not about race and its not about priviledge.
http://www.diverseeducation.com/artman/publish/article_6954.shtml