Nazi is short for “National Socialist”, socialists are left-wing, left-wingers are Nazis. Q.E.D.
(Quod Erat not fucking Demonstrandum, you disingenuous nincompoops.)
It doesn’t help that some of them have a desperate need to believe that their side only does terrible things because they have no choice - because liberals would do “far worse” to them given half a chance. As if “shut up and stop making people different than you miserable” was actually code for “later I’ll kill you and everyone you love” or something.