I do believe this post uses a limited definition of politics, although quite legitimately. Most people tend to essentialize polititics, for example, a policy will be considered left/right wing because of its proponents rather than its content. However, discussing the internal rationality of a politico-philosophical system is interesting, but it implies a redefinition of politics as a cost-benefits analysis of the use of a particular model of reality for the purpose of construction of laws.
In such case, the “What about the Nazis” argument is no longer a problem, because you can prove that the politico-philosophical system of national socialism has some benefits (nazi Germany became a huge economical power) for a huge cost (genocide, war, nationalism, etc...).
Discussing a particular subject is therefore a problem, but discussing the models is interesting in a rational debate.
This assumes that a model of reality is necessary to build laws. I permit myself this assumption because a) laws are part of the system called the Law b) the Law cannot deal in specifics (there cannot be a law directed to a specific individual, or a list of specific individuals) c) therefore the Law is a model of the society as it should be. d) such a model cannot be constructed without knowledge of how society is, and why, and how it goes from one state to another. e) This knowledge itself must be a model to be usable.
Denying politics is also a mode of oppression. I had a teacher calling women in my class “females” which is very insulting in French as it only ever applies to animals, not peoples. When one of them complained, he dismissed her by saying it was not the place for her feminist militantism.
Another note on Martin Luther King : he said several times that the greatest enemies of black liberation were not the KKK but those (mosty middle class, benefiting indirectly from racism) who saw the problem but advocated innaction because revendication wasn’t polite or there was better problems to adress.