Discrimination, bigotry, prejudice, bias, even hate and discontent is an emotion based on preference and ignorance. Retribution is not based on preference or ignorance it is a conscious and premeditated persecution of a person or group thought to be the source of discrimination, bigotry, prejudice, bias and even hate and discontent.
The problem is that some self interested activists of the discriminated group thinks that they are morally justified seeking retribution from the posterity of the accused discriminating group. All things being equal that might not be the case but because of persistent inequities the discriminated group has an ax to grind and some a willingness to grind it.
Some of the problem is that there are a few who profit from the situation and strive to maximize it as opposed to seeking solutions for it. There are a few who benefit from it and are interested in keeping things as is. The are many who are sympathetic to it and offer no resistance or encourage any redemptive actions. There a few who perceive the problem and vocalize their opinion only to be chastised, rebuffed, or threatened.