You're twisting Johnson's words to say she didn't feel it; she was able to use a "whites-only" bathroom and didn't experience as much direct personal animus from her co-workers. That doesn't mean she didn't feel it, only that it didn't take certain forms.
But twisting that is also to miss the entire point of highlighting this moment in history: She was great, but not singular - she succeeded in large part because she had a tremendously lucky break others were denied. Much like a poor person winning the lottery doesn't create upward economic mobility, a black women getting a good job doesn't end racism.
(I already wrote about this at https://news.ycombinator.com/item?id=14482955 and I suspect there is some concerted effort to parrot talking points against the film as I've seen similar bizarre comments on many sites.)