Here is what makes more sense to me. References to shit are implicitly references to sanctity, to sacrality. The Nazi reaction was one to crumbling institutions and mores, to pervasive Bolshevik efforts to destroy German culture. What Hitler wanted to invoke was the sacred nature of Germany itself, which he valued all the more, like all recent converts, having been born in Austria.
Purifying is no different than a bird nesting, getting rid of unwanted “intruders”. Dogs will not shit in their containers. Why? It is an act of impurity, understood completely at an instinctual level. We share this need, this drive, with most animals.
Now, Nazism was lunacy, but all ideas taken far enough become lunatic. Communism is the opposite idea: that we have no need of culture, need regard nothing but homogeneity as sacred, and that individuals have no right to assert any differentiated identity. This is lunacy as well.
Something can be a good idea in moderation. Nationalism is not something we begrudge Mexicans. If they want to root for their team in the World Cup, then most Americans say great. If they want to put that flag up on their wall at home, even though they are no longer Mexicans, fine.
But Americans have the same right. We have accomplished amazing things. There is nothing wrong with taking pride in that, and indeed something pathological in feeling shame for things we have not done. No nation and no individual is perfect. That does not mean that they are not BETTER as people and nations operating in the world with self respect, and an on-going intention of growing.
To make the latent obvious: self loathing is not a mechanism for growth. It is rather the AVOIDANCE of growth. It is the tactic of psychologically infantile people to substitute masochism for genuine self reflection.
My two cents. Work to do.