Godwin's law and its corollaries would not apply to discussions covering known mainstays of Nazi Germany such as genocide, eugenics, or racial superiority, nor to a discussion of other totalitarian regimes or ideologies, if that was the explicit topic of conversation, because a Nazi comparison in those circumstances may be appropriate, in effect committing the fallacist's fallacy, or inferring that an argument containing a fallacy must necessarily come to incorrect conclusions.An example is a discussion whether waving the Confederate flags was "hate speech" or "fighting words", and hence undeserving of First Amendment protections.
Well, consider the famous march by the American Nazi party through Skokie, Illinois, displaying the Swastika flag, where 1 in 6 residents was a survivor of the Holocaust. The Supreme Court ruled that this was free-speech, that the Nazi's had a right to march.
Citing the Skokie incident isn't Godwin's Law. It's exactly the precedent every court will cite when deciding whether waving a Confederate flag is free-speech.
I frequently discuss totalitarianism, as it's something that cyberspace can both enable and defeat. Comparisons with other totalitarian regimes, notably Soviet Russia and Nazi Germany, are inevitable. They aren't Godwin hyperbole, they are on point. Those who quickly cite Godwin's Law are committing the "fallacist's fallacy", or the "Godwin's Fallacy".