No, life is not binary.
But if you were in 1940s Germany hiding from the Nazis, would you feel safe NOT assuming any given German goy, a stranger to you, wasn’t a Nazi?
Black people, for their safety, HAVE to live in the assumption that every white person they meet, that they don’t know, is likely to, for example, call the cops on them for breathing.
While that remains the case, we can’t expect or ask them to be polite or nice.
How do they know we don’t have white hoods in the back of our closets? They don’t.
Germany is no longer a Nazi nation. America is still a racist one.