There is some sort of fundamental honor as well to allow to allow someone the tools to at least maybe shoot a Nazi on their way out, as one last act of resistance before certain death. Arms are a right even when desperate circumstance make it almost only symbolic.
Edit: also some may enjoy this amusing bumper sticker, created by a Jewish organization in America who themselves criticize Nazi gun control (https://store.jpfo.org/40-large_default/-all-in-favor-of-gun...).
Careful. I pasted a quote. Those are not my words. I didn't accuse anyone of being cowardly.
The more reasonable version of the argument is that the unofficial purges, before the evil becomes fully embraced by the government (the Nazis), or where hidden and unofficial (the KGB), can be deterred by armed civilians. If you know the Stasi are coming to take you away in the night to certain death you'll be willing to fight, and if armed you have a real chance at inflicting casualties. And if every raid leads to dead troops and PR disasters the state is less likely going to get to the point where the terrorists adopt the mantle of government (Nazi Germany) and can then bring the sum total of state forces to bear.
tl;dr the argument is more about resisting unsanctioned or non-governmental terrorism so it doesn't become governmental.
This argument is so tired it has it's own Wikipedia entry: https://en.wikipedia.org/wiki/Nazi_gun_control_argument
> "The Jews of Germany constituted less than 1 percent of the country's population. It is preposterous to argue that the possession of firearms would have enabled them to mount resistance against a systematic program of persecution implemented by a modern bureaucracy, enforced by a well-armed police state, and either supported or tolerated by the majority of the German population. Mr. Carson's suggestion that ordinary Germans, had they had guns, would have risked their lives in armed resistance against the regime simply does not comport with the regrettable historical reality of a regime that was quite popular at home. Inside Germany, only the army possessed the physical force necessary for defying or overthrowing the Nazis, but the generals had thrown in their lot with Hitler early on."