Except for Plessy, all the things you mention were the result of state and local government action, not Federal government action. The Federal government put paid to those questions with Brown and with the passage of the postbellum amendments. And, when it was clear that states were not succesfully integrating on their own, or providing equal protection to all races, the Federal government took the issue away from them and passed the Civil Rights Act in 1964.
So, if anything, to the extent that reparations proponents are seeking restitution for government action, they should be seeking it from those state governments, not from the Federal government. They were the ones that done somebody wrong. Perhaps the Feds should have responded more quickly, but they did respond. The states, on the other hand, had to be forced to integrate.
When Little Rock schools were being integrated in 1957, it wasn’t the Federal government trying to prevent nine black students from entering–it was the Governor and the National Guard of Arkansas. The President send in Federal troops to protect those children. So the beef ain’t with the Feds, it’s with the State of Arkansas.
(FYI, there are still Jews, living victims of the Holocaust or their children, seeking additional reparations. Remember all the furor over the Swiss bank accounts recently?)
And when you say, “You cannot honestly argue that the descendants of slaves did not suffer from the oppression of their ancestors. They still do,” that’s a little bit too broad of a statement to wrap my head around. It doesn’t address people as individuals, but as members of a group. Which black people are the descendants of slaves? How do we know? How do I even know that this Charles Barron guy was ever related to a slave, and instead isn’t just a race-baiting muckraker? I don’t. How do I know Michael Jordan isn’t descended from slaves? He certainly hasn’t suffered or been oppressed.
I’d love to live in a society where the quality of educational opportunities, where college admissions, loan applications, job opportunities, and everything else, were truly color-blind. I don’t think that reparations for something that occurred more than 130 years ago is the way to achieve it.