It would take only the most cursory examination of documented revolutions, communist ones as much as any other to immediately see that that's not the case. Millions get swept up in it. People starve, civil and international wars are fought and combatants die, civilians become collateral damage, power struggles emerge within the ranks of the revolutionaries and loyal partisans are swept aside so ambitious people can ascend. Revolutionary zeal leads to countless cases of misidentification of suspected 'reactionaries', economic turmoil creates desperation leading to violence and crime and then further violence in the attempts to restore order. In the chaos and lawlessness of the initial stages of a revolution people will take the opportunity to settle old scores. Individuals who previously held no power now take up new roles in the new society and wield even tiny petty amounts of power yet still more than they could have dreamed of before and turn out not to be responsible with it and others still manage to claim masses of it.

And this is only the people who you would hopefully agree didn't 'deserve' it, but for me on a personal level, though it does make me rather useless I suppose, I'm not in to killing, so even those who arguably did 'deserve' it, the 'ruling' classes, I may be glad to see them stripped of the privilege and influence but I don't want to see them or anyone strung up. And in the period of re-defining and re-shaping society after the revolution the new order will seek to identify just who counts as 'ruling class', this has, in the past included people who owned a shop, people with 'bourgeois' jobs in the former government, teachers accused by students of being 'reactionaries'.

It might just be that communism really can, if not de-railed create a utopia on Earth and it might just be that all that happens above really is actually what just needs to happen for us to get there, but I'm not sure I could stomach it.