Che died relatively young, and lived violently. His was a world of ideals. He embraced Communism, having been raised a socialist by well to do parents. It is his adult life which earns him the description of 'monster'.
The places where Che had most influence are in poverty, suffering deadly strife which threatens to engulf the regions they inhabit. This wasn't Che's intention, having a goal and a method of prosecution to that goal. Che's goal might be inferred by the poetry he is said to have enjoyed, like that of Pablo Neruda. It is an idealistic world, without social inequality which leads to injustice. To achieve that goal, Che employed brutal injustice.
Soon after Cuba was overthrown by Fidel Castro, Che was given responsibility in government.
"He was appointed commander of the La Cabaña Fortress prison, and during his five-month tenure in that post (January 2 through June 12, 1959), he oversaw the trial and execution of many people, among whom were former Batista regime officials and members of the "Bureau for the Repression of Communist Activities" (BRAC), a unit of the secret police known by its Spanish acronym. José Vilasuso, an attorney who worked under Guevara at La Cabaña preparing indictments, said that these were lawless proceedings where "the facts were judged without any consideration to general juridical principles" and the findings were pre-determined by Guevara. It is estimated that between 156 and 550 people were executed on Guevara's extra-judicial orders during this time."
Che killed for his cause, and it is apparent he wanted to die, such that at several times, his colleagues worked hard to convince him not to die for one cause or another. When he died, he still had those handsome, youthful features.
People still revere Che. People denounce decent people for being monsters. Che deserves the epithet. The short documentary The Weasel is making will show Che, The Monster.
Compiled episodes part A
Compiled episodes part B