I'm unsure why you pick those "400 years" as more important than the other years, where other races were enslaved, furthermore, black people were and still do treat black people like crap. Slavery wouldn't have worked otherwise (they were promised things their own race weren't giving them).
Affirmative action for socially critical professions like doctors and lawyers still makes some sense
The hispanic or latino population is about 17% of america, african american percentage is about 13.2%, and asian americans are approximately 4.6%.
Some black communities might need black doctors and black lawyers.
A black male born in 1991 has a 29% chance of spending time in prison at some point in his life. One out of nine African American men will be incarcerated between the ages of 20 and 34. Black males ages 30 to 34 have the highest incarceration rate of any race/ethnicity. Black people make up to nearly half of the 2 million inmates in U.S. jails or prisons
You can say these statistics are false or make up other reasons, like white policemen are racist. The statistics show that in every country, including countries where black people are the majority, they are not as successful in school or staying out of prison.
It of course makes sense to have reserved spaces for different races, but races change, crime rate changes. Your argument that they don't trust white people is absurd. There's still going to be a predominantly white jury. If there's a white jury, wouldn't it make sense to have a white lawyer? I mean, a racist jury might find a white lawyer more honest.
I think affirmative action is rubbish. There's other universities to go to, and "trust", "faith" and supposed "racism" are nonsense. You shouldn't say "well more black people should be allowed to study because there's more black criminals and this criminal doesn't trust a white lawyer!"
Anyone who could possibly deserve a place will learn and practice all they need to know, otherwise they'll get thrown out or even more likely they'll quit
What about the gifted person that is superior at learning but doesn't get the opportunity to learn because of racism? It seems to me, you want to promote racism to help against supposed racism