Well, the problem is that most of the time people of color talk about an action as "racist" and start to discuss privilege, someone will 1) assume that they are being called racist whether they are or not and then 2) turn the entire conversation to how hurt they are by being called racist, which 3) effectively derails the conversation and makes it all about white people. Again. In my book, doing racist things/saying racist things makes someone a racist. I hope, however, that they can change and become an ally with education, though that is not always possible. And it certainly isn't possible if the entire conversation is about "no! don't call me a racist!"I take people at their word. If they say they aren't racists, then at the very least they don't believe themselves to be racists. Which means, presumably, that they don't want to be perceived as racists. Instead of arguing about who is or is not a bigot, I'd rather spend some time teaching people how not to look like bigots.
This is neither a confessional or a courtroom: I'm not here to grant absolution or to declare individuals guilty. Thus, there's no reason to beg forgiveness or to defend yourself. I have no reason to believe that anybody participating in these discussions is a Nazi, Klansman, White Power skinhead or any other flavor of violent racist. (I doubt someone with swastika tattoos and a Hitler poster would find much of value in conversations about being a better ally to people of color... ). So you need not spend time declaring you're not one of Those White People, because nobody here thinks that you are.
The comment James made about "original sin racism" points to a real problem with a lot of anti-racist material: it follows a Christian model of redemption through repentance. Readers are taken to task for their sins and shortcomings. By accepting their failings they hope to be forgiven and to separate themselves from the inherently corrupt society despite their own inescapable taint. And all too often breast-beating becomes a substitute for actually doing something.
Don't get me wrong, I think there's definitely a time and a place for recognition of one's privilege and of the part one plays in upholding an unjust social order. But I think you can make change happen from without just as quickly as from within - and arguably a good deal more effectively. I don't need to challenge all my preconceptions before I can treat people with respect and show concern for their feelings. And once we get past some of the more common pitfalls and establish communication a lot of those prejudices might just take care of themselves.