You make an important point, but I want to add a caveat. We know a lot about how long we have to wait to deal with "regime crimes" in order not to jeopardize the political system of the successor state.
It seems that in the case of maximum scale crimes, the right number is somewhere around 30 years (one generation). That was approximately the time between the end of WW2 and the 1968 student revolts in Germany, and the Bonn republic survived it. As another example, given the divisive nature of the incredibly bloody Spanish civil war, societal "digestion" of the Franco dictatorship also had to wait for almost 30 years.
What happens if winners rapidly turn on the former suppressors can currently be observed in Egypt.
So far, so interesting, but what it doesn't tell us, is what the time scale for a (comparatively small) intrasocietal adjustment of morality is (gay marriage = sin -> gay marriage = fundamental right).
One decade? Five years? Fifteen? I can't think of any precedents that can truly be compared to the gay marriage situation.
My personal feeling is that the reaction to Eich was not appropriate considering where he stands on the currently applicable bigotry scale.
But that is also just a gut feeling. The question remains: What is the right time to wait before a step of progressive change in society should be "enforced", so that the backlash remains minimal?