Well jdang is at least a republican who knows what's up.
I spent many years studying and researching the rise and fall of communism. I generally use Socialism in a more "pure" sense, in that it is a direct descendant of Marxism. Stalinism, Leninism, Democratic Socialism, National Socialism etc. are all derivatives, and not all are good things.
I would have said "Why do Republicans not know what Marxism is" but then I don't think as many people would have known at all what I was talking about.
Personally, I'm a Marxist at heart but a Social Democrat a bit after the style of the German SDP.