Godwin's Law.

Godwin's Law: "As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1"

Note that this is descriptive, not prescriptive. It doesn't say there's anything wrong with using a comparison to Nazis or Hitler.

So "invoking" Godwin's law as a critical response to such a comparison is not a meaningful argument.

I don't think we should make casual comparisons, of course. But I think we do ourselves a disservice if we pretend we can never compare them except in reference to themselves. Viewing them as sui generis only offers us the comfort of thinking it could never happen here. But it's far more important to recognise that it could happen anywhere, and that even if it never got as bad here - no attempt to annihilate an entire ethnic group - it could get bad enough.

And the Nazis didn't begin with concentration camps and ovens, and many joined the party and participated in attacks on "undesirables" without having an urge or an inkling that it would turn into genocide. Rather than mistakenly comparing full blown Nazi-ism with nascent violent nationalism, and reaching the obvious conclusion that they're not identical, we should look at the early moments of fascist movements, and see if our current moment looks anything like them.