Well, my own experience is that talking to white people about racism gets like that frequently and rapidly.

Plus, there are the occasional bonus experiences of having people you trusted bust out with the most surprising nastiness when you least expected it.

Like the one who assumed that rape was "more accepted" in black communities.
Or the one who basically figured that black people were (all!) just crying wolf about racism, because, you know, she didn't see any.
Or the many who assume that any reference to racism constituted calling HER racist.

It's horrible, absolutely horrible.