I didn't say you called him a Nazi. I'm saying that we should be willing to distinguish a known Nazi from a suspected racist.
As to "racism," no, not necessarily. I'm going to assume you're white (don't read anything into it, it's just for example). Let's pretend I'm something other than white. If I call you a [anti-white slur] because I hate you for your politics and I want to hurt your feelings, that makes me a jerk, not necessarily a racist.
Now, is it a sign I could be a racist? Sure. Should you give people the benefit of the doubt that they're not racist in that scenario? I don't care, if you act like a jerk I don't care if someone calls you a racist. But my point is that it's probably not all that great of an indicator that someone is a genuine racist.
Now, if you're a liberal, you might reject my narrow definition of racism outright. You might think it doesn't account for institutionalized racism and that saying "America was great even despite slavery" makes one a racist regardless of the concept of racial superiority. I would disagree, but that's a different discussion than the above (which is premised on the traditional definition of racism).
So you think if you use a racial slur or a word that is seen as a racial slur. It does not make you racist if used in the right context? What?
People should stop and quiz whether you are in fact racist or maybe just stupid for using the word?
Is that what you are saying?
Haha!!