On the basis of what I read, what I hear from mental health clinicians, and more extended conversations with members of my family, I have long thought that the obsession of those on the left with finding racism in their political/cultural rivals - in fact, in just about everyone - is a form of escape, of distancing. They want everyone to know they aren't one of those rubes.
But reading some of the offerings from hbd chick's recent linkfest, especially this little number about 3 Reasons Why Diversity Doesn't Work, it occurred to me that the pull might be in the other direction. It may be that being an anti-racist is one of the markers of the cultural elite in that crowd. It's not something where you can just act decently to all sorts of people and say no more about it. Displaying antiracism is a signifier that one deeply belongs. Making statements about how racist other people are, and displaying a greater sensitivity than normal for detecting it, may be an aspirational strategy - a way of getting ahead.
Rather like the princess and the pea.
It would explain why conversations about immigration so quickly move to accusations of prejudice. It is not enough to merely make no statements which can be interpreted as bigoted; one has to display positive behaviors of being better than average. Heck, it might be a mating or status-enhancing strategy within that tribe. I have been thinking of the value of the display as a way of weakening other tribes, but it may instead be a method of acquiring resources within the tribe.