It's convenient to just say Che was a "revolutionary" and since the US was borne of revolutionaries, it's the same thing. The clear and concise difference is the Che and the communists actively murdered and suppressed citizens just for being....not them. Che specifically had the job of executing people deemed "not revolutionary enough". Not soldiers. Not tyrannical politicians. Just dirt-poor people who happened to disagree with his point of view. No comparison.
I've heard people try and use this same dumb argument that the US revolutionaries were just 'terrorists', right? Guys with rifles killing people in their land - just like Palestinians! Of course, this is bogus too. If the Palestinians just targeted Israeli soldiers and politicians this would be an entirely different issue. Instead, the blow up school buses full of children. Samuel Adams never sawed random people's heads off because he really disliked England.
As for Che still being a big hero in South America - fuck those who understand what he was and feel that way. If you worship Che out of ignorance, ok, I'll buy that. Everyone needs a hero. If you honestly know what he represented (the world's most efficient and prolific meat grinder of all time) and did for a living, then yes, fuck you, you murderous bastard