Are you comparing discrimination against black people in the 50s to what may have happened to a man? A lot of civil rights activists wanted affirmative action too.
Often is most of the time. People perceive relative changes as terrible. That's why they arrested Parks instead of agreeing with her.
Why? It's an analogy, the relevant parts match; There's no rule that says discrimination has to reach a certain level before it should be resisted . Stop derailing my point with irrelevancies.
"A lot of civil rights activist" - which ones and why? Maybe their reasoning is sensitive to their particular interest.
I understand what 'often' means, I don't agree with it as a generality. Even 'People perceive relative changes as terrible' isn't always true.
Seriously though, 'often' is just a weasel word if you don't specify the context. This might qualify as a mechanism for dismissing valid complaints...