And after winning the war, Stalin proceeded to kill millions for good measure.
France buckled in months and Wehrmacht then attacked Red army which did not have setup defense positions because they themselves were preparing to attack...
Just like Stroustrup's formulation, this can become a cover for unnecessary and mistaken excesses, but I don't necessarily think that's inevitable.
Every other Communist state that I am aware of also killed millions in internal purges: Cambodia and N. Korea, notably. I'm actually not sure what happened with Vietnam and Cuba. I'm not sure if contemporary Venezuela counts as Communist, but I am under the impression that there was killing or at least persecution of internal political enemies. I don't see how US sanctions have anything to do with how one treats political enemies.
I guess Eastern Europe might be an exception, but I think that is because Communist states were imposed with external force, not revolution from within, and the population mostly capitulated. However, I believe that political opposition was still likely to be deadly.
Since Communist states seem to be highly correlated with killing internal enemies, it seems like a feature of the system, not a response to external pressure, particularly since the largest two did not have serious external pressure at the time.
So yes, of course, no political ideology has "let's murder millions of people" as its founding principle. But some political systems require it.
It's important to remember the Anti-Comintern Pact started as an anti-communist agreement between Germany and Japan. Look what that did.
I’m not advocating for this transition. I’m on the side of peace and pacifism. I see no man as above me, or below me. Marx may be right but who really wants to try and test it? History has shown that regimes who try, fail. Those who stop short and just be all dictatorships, end up destroying their own. So, I guess cheers (champagne glasses) to the sinking ship.
If you’re asking the latter question in good faith, I’d encourage you to consult Wikipedia; it has good articles on both the term “proletariat” and Marx’s phrase “dictatorship of the proletariat”.