I believe you underestimate the danger that Allende posed to Chile by labeling it hypothetical. The standard operating practice of Communist regimes, and certainly those popularly elected, is to gradually introduce Marxism. Lenin waited until the Tsarists were defeated militarily before he cracked down on rival leftist parties like the Mensheviks and the Left Social Democrats. In the case of Cuba, Castro kept his Communist affiliation secret until well after he successfully marched on Havana. Only after several years of rule did Putin restore the symbols of the old Red Army and restore military and political leaders of the Soviet era to a position of honor. While most of the Communist regimes in post-World War II Europe were placed into power via Soviet bayonet, the Communists formally and publicly adhered to democratic processes in Czechoslovakia. Only after the social democratic party fell out of power and democratic leader Jan Masaryk was assassinated by the Communists did the Reds cast off the niceties and impose a dictatorship.
The worst Communist atrocities usually occur at least a decade after power is consolidated. The Chinese Cultural Revolution began 17 years after the Communists expelled the Nationalists. Stalin's extermination of the kulaks and the massive expansion of the gulags took place 15 years after the Bolshevik coup in St. Petersburg. The same track of gradual imposition of Communist power can be seen in Venezuela and South Africa today. (Would that the Venezuelan military harbor a Pinochet who would clean the clock of the tyrant Chavez. Pat Robertson was 100% right on this matter.)
Given the long history of Communist techniques for coming to power, there was no reason to imagine that Allende would have acted differently. Pinochet was entirely justified in his military coup. It is undeniable that he was brutal in his suppression of the Communists, but so was Lincoln and the Reconstruction governments to Copperheads and former Rebels, respectively, as were the Confederates to Union sympathizers, as evidenced by the burning of Lawrence, Kansas, and the hanging of dozens of Unionists in Gainesville, Texas. Cromwell was at least as ruthless to royalists and Catholics as the Stuarts were to the Puritans and other Protestant dissenters.
War is about killing people and breaking things, as Rush Limbaugh once put it. Civil wars are often uniquely brutal.
There's a reason for that time lag. A totalitarian state must first ensure that the common population is disarmed before committing large-scale atrocities, and so it needs a relatively quiet period, followed by gun registration and confiscation (as the USSR did in 1929) before engaging in real large-scale killing (as the USSR engaged in in the 1930's
>>(Would that the Venezuelan military harbor a Pinochet who would clean the clock of the tyrant Chavez. Pat Robertson was 100% right on this matter.)
The Lefties on some neutral forums I'm on, screamed like stuck pigs when Pat made that statement, a sure indication he was onto something.