If you walked into any establishment with a t-shirts bearing the "Nazi" Swastika, you would almost assuredly be asked to leave for obscenity, as well as degraded and possibly assaulted by your peers.
So, why is it socially acceptable to wear a shirt like this, which brandishes the logo of a fascist totalitarian regime responsible for the genocide of millions?
because it wasn't.
...
the guys we killed deserved it
Because communism is hella good and Nazis are shitbirds.
Where to even start?
Because Nazis are losers lol
I'm going to ignore the bullshit of your second paragraph and answer your question:
1.) Just because something is despised, doesn't mean it's right. I could shit on the sidewalk naked and I certainly evoke disgust in many people, that doesn't make my action more sensical.
2.) Communism doesn't actually argue for genocide. Nazism actually does. For negligent crimes you get punished less than for intentional crimes.
There are several places where this would indeed happen to you if you wore a t-shirt like that.
Places where ignoramuses like you are dominant.
I agree, you should be able to wear your little Nazi shirt anywhere and put a gun in the mouth of anyone who tries to discriminate you from being present there just cause of it.
Not even going to argue with you whether or not communism killed more people. They all deserved it. Every kulak hung on a rope, every imperialist spy buried alive, every petty bourgeois retard gulag'd and forced to make macaroni art for Stalin.