Yeah, Che killed people. Some of them innocent people, I'm sure. But the people he were fighting against were just as cruel and bloody, and it ain't like we've never slaughtered folks, either. One man's murderer is the next guy's freedom fighter. Hell, I grew up here in the South and, as the descendant of Confederate soldiers and partisans, I grew up being regaled by stories of how noble and virtuous both they and their cause was. Bull. They were every bit at wicked, cruel and depraved as Che or any of the rest of the scumbags listed here were. Enslaving an entire race of people based on the principle of racial superiority and then committing high treason in order to preserve slave labor is as grotesque and monstrous a crime as any listed above. And people still romanticize THEM every day in our country ... And that's not even getting into the horrors committed by Union troops, the tragedy of Reconstruction, etc.
.Somehow, I can't find myself any more offended by a Che shirt than I am by the Rebel Flag.