But how about political slur?
Here's the problem. Unlike sexist, racist, or autistic slur, our common sense does not overlap in politic.
Let me gives me an example.
People in America and Europe considers Hitler is taboo. Well, not for Asia. We don't consider Hitler as "radical hate speech". Some people has no problem using swastika. Most people when seeing other uses swastika may go "Ooooh.. Bold choice," but done.
I personally find saying "You realize that your argumentation for A is scum, is like the argumentation that Hitler used," is acceptable as long as the comment creator believes that his argument indeed similiar to the argument that Hitler used. So it's not ad hom attack. It's attacking the argument. When I say your argument is like Hitler', it's an implicit way of saying 'Dude. You are going to a fallacy that Hitler went. I don't want to explain what is exactly the fallacy that Hitler went, but I hope that you get the message'.
Mafiascum.net is a global online community. Can we have an explicit rule for this? I can guarantee that it is not that obvious for us foreigner.