Granted, this is largely because socialism and communism by necessity require levels of totalitarianism. When you try to implement a system to the extremity at which those regimes tried to implement it then by necessity the totalitarianism that comes with it becomes more extreme.
You can never have a socialist or communist system that isn't totalitarian in some way. Unless, of course, it's a completely voluntary association of individuals living in a commune-type environment.
Erm...I suppose one might be able to argue that, by stretching the definition of "totalitarian" somewhat.
And yes,
true communism really is people living voluntarily together in a commune. Any kind of central government makes it no longer truly communist (at least, based on my understanding of communism).
Socialism does require a central government, but does not require totalitarianism, unless you want to define any level of government control as being "partly totalitarian," much as the social programs enacted in the US over the past century+ make us "partly socialist".
