Because if there were any actual justice and people were properly informed, wearing a shirt of Che would be only a couple of steps below wearing one of Hitler.

Yes, he was that evil. In fact, I believe the only reason we don't rank him up there with Stalin and Hitler is his simple lack of means - he openly stated that, were the missles in Cuba under Cuban rather than Soviet control during the Cuban Missile Crisis, he'd have nuked the USA - if he were able to, he'd have killed vast numbers of people and enforced a socialist dictatorship over as many as he was able to.