Should I admire someone like Che Guevara?

Admiration is not subjected to moral judgment. One either admires someone, or don't. We might admire someone based on the wrong perception of the person, or without the full knowledge of the facts, but that doesn't mean it's wrong to do so. One might even admire someone who is clearly immoral or amoral. It depends on WHAT you admire, not WHO you admire.