Allow a Communist to speak their view:
As a Marxist, I myself do not own a Che Guevara shirt- and there are a few reasons for doing so...
In the U.S., Che merchandise has become so co-opted that it has ceased to have any revolutionary meaning to it anymore. While Che's visage still carries enormous emotional and political impact in Latin America and the rest of the world, in America he is essentially "that Rage Against the Machine dude". Thus, for me as a Communist living in (as Che used to say) "the belly of the beast", it would be useless for me to wear one.
Another thing is the contradictory lines that Che took during his lifetime. Don't get me wrong; Che was a great revolutionary, he had an enormous love for the oppressed and had a great heart. His spirit and unshakable internationalism are things that all revolutionaries should seek to emulate. However, Che had a few fatal flaws:
1) Che did not see the USSR as a new state-capitalist empire under the guise of socialism (as it was after 1956), but rather simply a "rather flawed" socialist country worthy of still being an ally with. He felt that the dispute between the pro-Soviet forces and the genuinely-communist forces in the world were simply a "family argument" (when it was in fact a critical life-and-death question as to the fate of socialism). Thus, Che went along with Castro's openly-revisionist strategy of aligning with the USSR, and Che was utterly oblivious to the fact that his "comrade" (who was not just a "flawed revolutionary", but an actually revisionist) had essentially turned Cuba into a Soviet neo-colony.
2) Che's military strategy of focoismo was incredibly flawed. Che argued that small groups of determined armed fighters (called “focos”) could take to the mountains and use armed actions to rally other forces, thus artificially triggering the crisis and collapse of oppressive governments. Focoism had the added attraction of offering a hope of relatively easy victory, and it essentially said that all a revolutionary had to do was to pick up a gun, go into the jungles, and as long as they were brave and filled with willpower, the revolution would come. However, that is not how