What a ludicrous straw man. The Bolsheviks came to power on a wave of popular support. They were elected by the overwhelming majority in the soviets. They did not simply claim to speak for the oppressed, they actually did.
Terror is used by every revolutionary government; it is a necessary component of a civil war, since the defeated classes will always try to regain their lost position. The revolutionary Jacobins in the French Revolution had to resort to a reign of terror for a time, as did the Bolsheviks.
Revolutionary terror is qualitatively different from individual terror. It has a diametrically opposite character and aim. It is used by the revolutionary class to crush the resistance to their rule. The Red Terror was fully justified as a measure to crush the resistance of the bloodsucking Russian nobility and bourgeoisie, the same bourgeoisie that had sent millions of Russian workers to go kill German workers on the blood soaked plains of WWI.
Marxists are not bloodthirsty. We generally abhor violence. By the same token, we understand that violence will be a part of life as long as classes exist. The crocodile tears you shed over the Russian bourgeoisie are being shed for the members of a vicious ruling class that was making many fortunes off of the blood of Russian soldiers, sucking dry the national wealth. While Russian soldiers were dying in the bloody mudholes in Europe, and workers in Petrograd were starving, the nobility and bourgeoisie was living it up in the palaces and fancy restaurants.
Violence is used by a Marxist in the way a surgeon must use violence against a body in order to rid it of a more heinous ailment. We would be more than happy if the bourgeoisie would consent to submit their property to a democratic vote, and hand it over if they lose. But this will never happen. No propertied class in history has given up its position without a bloody revolution.
We hail the American Civil War as a progressive war, for example, since, despite the massive loss of life, it released millions from bondage. To this day, racist supporters of the southern slavocracy refer to Abraham Lincoln as “the first American dictator,” since he led the fight against the slavocracy. The criticisms of Lenin have a quite similar origin.
Another ludicrous straw man. The Marxist program is for workers democracy, through working class organizations that place political power directly in the hands of the working class. Soviet democracy was a billion times more democratic than any parliamentary democracy, a billion times more representative, more attentive to the will of the masses. It was the direct class rule of the working class, i.e. the dictatorship of the proletariat.
Quite the opposite. The soviets took over the presses in March 1917, not by an armed takeover, but by winning the workers in the printing houses to their cause. Simply put, the workers in the printing shops refused to recognize any authority except for the soviets, i.e. the democratic organizations of the workers.
