People do a lot of things–eat, sleep, exercise, believe in proposition p or q, and so on. Sometimes those things overlap with the activities of serial killers, Nazis, and terrorists. This overlap may or may not be significant. If the activity is morally abhorrent, like, say, genocide, then comparisons are made. If the activity is innocuous, then well, nothing. Everyone eats, the Nazis eat, ergo ipso fatso.
Eating doesn't make people Nazis. Nor does speaking German. Or being German. Or believing in the capacity of government to do some things, like provide highways, ports, police, or health care. These things don't make anyone a Nazi because those beliefs do not just belong to Nazis.
So, for instance, the Nazis embraced euthanasia. They advanced all sorts of eugenic arguments for it. They also embraced a healthy lifestyle, and traditional marriage (sometimes)–and they advanced all sorts of eugenic arguments for these things as well. This does not mean traditional marriage is inherently Nazi.
This is something like the argument of a recent op-ed in the Vatican Observer (L'osservatore romano) on the occasion of the publishing of Nazi tract on euthanasia. Here's a taste:
Binding and Hoche, in fact, maintain that life cannot be considered life in the full sense of those who, because of diseases, are exposed to a painful and hopeless agony, or the life of incurable idiots whose existence drags with no purpose or usefulness, imposing on the community a heavy and pointless burden. With regard to these people, the two scholars invented a new definition which was to enjoy great success even after the defeat of Nazism: “lives unworthy of being lived”. A definition which paved the way to the elimination of the sick and the unfit, permitting these homicides to be justified with a morally appreciable motivation: they in fact spoke of “charitable death” (Gnadentod). These are the same words that recur today recur in the writings of many contemporary bioethicists, and of many politicians who support legislative proposals of a euthanasic type. As the editors write in the introduction, “the notion of life as a good that deserves protection is henceforth cast off from the anchor of any metaphysical postulation, any doctrine of natural law, and is led towards a semantics of concreteness and immanence: life has value as long as it procures pleasure and is free from pain”. We therefore see that this book, precisely because of its grimly up to date characters, must strongly embarrass those who champion euthanasia in the belief that it has nothing to do with Nazism.
And we have the full Godwin here: the only person who should be strongly embarassed is the author of this very sad excuse of an objection to euthanasia. To the extent that I am aware, no one is currently advocating that any state embrace Nazi eugenic policies regarding euthanasia; and no one is using those arguments to make the case for euthanasia.
You know what the Nazis also believed? Probably global warming. On that, see here.