Long ago in the days of USENET, one Mike Godwin stated what has come to be known as Godwin's Law: as a discussion goes on, it becomes certain that someone will draw a comparison with Hitler or the Nazi party.
If you'd asked me before I came back from a trip for the weekend, I'd have said I hope that we in the Second Life prim breast community could avoid Godwin's Law, though I'd never actually considered it. Silly me; SL is a virtual world, but we bring our real selves to it.
Look: playing the Nazi card is like playing the race card. It's an attempt to end or preclude discussion and irreparably tar an opponent. Anyone who had a valid argument in support of a position or claim would use it, so frankly, I consider the use of fallacious arguments, such as drawing comparisons with Hitler ("reductio ad Hitlerum"), evidence that the user has no valid argument.