Is this a fallacy as the poster claims?

The poster's argument states a classic questionable analogy.

The assumption behind your claim is that there is such a thing as a good Nazi. I would contend (as an empirical and moral matter) that there are no good Nazis because the Nazi philosophy is inherently wicked.

However, I would also contend that there are many very good nonwhite people.

Note that being nonwhite is an accident of birth, whereas to become a Nazi a person must make a deliberate moral choice to join an evil group.

Thus, the analogy breaks down on multiple fronts.

Analogies are usually weak arguments. This one is no exception.

I'm not inclined to trust the judgement of a Nazi on who's good and who's bad. I have yet to meet a "fine" or good Nazi. I don't think they can possibly exist. They subscribe to a totally evil ideology that glorifies hate directed at those different from them. For a Nazi to criticize a non-white person because they aren't white demonstrates why Nazi's are such horrible people. We don't have any control over our racial makeup. We're all part of the genetic Lottery. We had nothing to do with being white or black or brown. Being a Nazi is a conscious decision on a person's part. They control their own mind (hopefully), so they have total control over the decision as to whether they want to be a racist douchebag or not.,

Interesting scenario. To those who use the term "Nazi" as a derogatory term, it is synonymous with "bad person." Of course, Nazi's don't see it that way. This is a poor analogy made by the poster because the term "nonwhite folks" has no valence (good or bad as part of the definition) whereas "Nazi" clearly does to at least 99.9% of the population. There is a deeper issue of morality here as to if a Nazi can otherwise be a "good person" if we assume the "Nazi" part is bad. This is a rhetorical argument, not a logical one.

"The worst government is often the most moral. One composed of cynics is often very tolerant and humane. But when fanatics are on top there is no limit to oppression."

H. L. Mencken