It's disingenuous to use hindsight in such a way, and exactly why we have laws.
Laws are just philosophy and evolve over time.
Re; your Rosa Parks comparison - see my post including the ANC, IRA, Suffragettes etc. I cover that principle in detail, and the principle of using hindsight in a previous post.
There is an important, and fascinating thought experiment that helps with this principle (and sprung to mind with assassination of the guy in the US a few days ago):
Most people would agree Hitler was incredibly evil.
Most people would agree the world would have been better without Hitler.
Few people mourn Hitler's death.
The question - at what point do you consider killing Hitler to be justified?
(On that note, there is play on in London at the which raises the question "what would have happened if Hitlers mum had let Freud work with him as a child". Sadly I don't have time to get down to see it.)