An imaginary example may clarify
Bruce was told one morning about a crime that was committed, and told that he was going to be held accountable. He insisted that he had nothing to do with it, and he wasn't even there. He was told that it didn't matter. He fitted the racial profile of the perpetrators, and that was enough. He insisted that they couldn't even prove the crime was actually committed. They said that didn't matter either - he had to pay.
This is the kind of story which outrages people. If it turns out that Bruce is a white guy being held responsible for slavery or the so called stolen generation, which happened before he was born, then some people change their minds, and consider it is acceptable after all.
A similar, but even more bizarre logic appears in some feminist arguments. It is regarded as acceptable to make men compensate women for the misdeeds done to women by men in previous generations. So some man has to pay a women because her father was nasty to his mother? It is a clear demonstration of the opportunistic nature of some feminists.
Holding someone responsible for another's actions just because they happen to be a particular race or gender is unacceptable to most people - depending on the groups involved.