In other words, they're trying to be good, "well intentioned", but something makes them behave otherwise.
No, he's saying all white people have some racist virus in their brain, "even the most liberal well-intentioned" ones. He's not trying to be nice to those people and let them off the hook.
So us white people, every one of us - inherently, biologically, or genetically - dislike all non-whites.
Got it.