One does not have to deny the injustice and unfairness of both the past and the present to deny the case for reparations. The problem of reparations is they are forced payments from one set of citizens to another, and each set of citizens is determined based on general factors, not on specific factors and behaviors.
I, for one, have never chosen to accept benefits unjustly. Sure, I was raised in white America and had many opportunities that many African-Americans did not have. I also realize I have benefited from those opportunities; and, even more, I realize that many of my benefits came at the expense of generations of African-Americans. The thing is, however, that not only was I not privy to this information as a child, but I was not even given real choices as a child. The benefits were not so much bestowed as forced upon me. Thus, I did not contract in, I did not commit any injustice. As an individual, I do not possess such a retributive debt; as such, as an individual, I do not owe reparations. The only way to justify forcing individuals such as myself to pay reparations is to pronounce, "Well, you are a member of this group called 'white males' and this group is responsible for a lot of injustice." But, that is to generalize and stereotype to the detriment of one class for the benefit of another class.
As for the set of individuals who would receive reparations, again, it will not come down to specific cases, specific wrongs, and specific individuals. It will merely be, "You are African-American, and, as such, you have suffered injustice because your group has suffered injustice. Thus, you are owed a debt." But, then we will always have individual cases in which an African-American is given his freedom at 18, given an education, even given land. And, some of these African-Americans prospered and their posterity prospered even down to the present day. We can look even nearer in the past at African-Americans who were the beneficiaries of certain wealthy white individuals who took them in, educated them, sent them to prominent universities; and, such individuals have succeeded and passed such success on to their children and their children's children. Would these individual cases receive special attention, attention in which reparations would be denied? Personally, I think that would not happen.
For the sake of argument, though, let's say such attention is paid. Let's say the government basically says, "Hey, we will provide reparations to those African-Americans who are still living in poverty today, in order to give them a decent level of living." What about the white families who live at the same level of poverty, pre-reparations? Are you going to argue that not only is it just not to raise the standard of living for these individuals but that it is also just to take money from them to pay the reparations? To avoid this problem, would only complicate the matter more, as you might be inclined to argue that the reparation payments should just represent an extra tax on income and those who already do not pay income tax will not have to pay reparations. But, then we are saying that the ultra-rich were, again as a generalized group, more unjust to African-Americans (as they would be paying much more, they must owe much more, right?) And, that the poor were not unjust? Plenty of poor white folk hung ******s. Also, what about the noveau rich? Is Bill Gates going to pay a higher reparations penalty than his parents would have? That certainly sounds absurd.
In the face of our past, we ought acknowledge the mistakes and the injustices. We also ought acknowledge that, as the privileged class, we have benefited to some degree (some more than others, some less, and, yes, even some not at all). But, we can do this without saying that as individuals each of us has acted unjustly. And, as such, we can say this without saying that each of us owes anything.
If justice exists, we have a duty to justice. Insofar as we fail in that duty, we can be called to account. But, calling an individual to account for the actions of others who merely look like him is not something that serves the purpose of justice; in fact, I would argue it is categorically unjust.