: A revolutionary party cannot accept ALL elements of the working class any more than an intentional community can. Is Twin Oaks or East Wind 'vanguardist'? In the sense that they demand ideological agreement as a precondition of membership, yes. Does that make them mind-crushing dictatorships? What a laughable idea!
: Think of the truly innumerable rules these communities would require if their membership was promiscuously open. These communities are able to operate with few rules---and little open authority---BECAUSE they have rejected potential members who would clash hourly with the commonly held values of those who formed these voluntary associations. The more ideological harmony in advance, the less authority will be needed later on.
The following is pure speculation on my part, but I'm been thinking along these lines for some years now: communism or other egalitarian societies may only be able to function within a maximum number of people, e.g. a tribe. These systems may require that everyone involved know everone else; once you get beyond a certain number of people, anonymity sets in, and with anonymity, indifference. An analogy would be the ease with which a soldier can fire a rocket at a distant enemy, versus the far more difficult task of shooting him from ten feet away.
I'm no sociologist or anthropologist, but I have a hunch that man is a tribal animal, with the tribe being no more than maybe several thousand strong, and that beyond that, you will always have inequality and brutality.
I've never lived in a pygmy tribe or an indian tribe, but I spent some months on a kibbutz, and I was very impressed with what seemed the equal distribution of labor (which you might call job rotation). Some weeks I did the hard work of clearing stones from a field; others I did the mind-numbing work of sorting apples in a factory (this setting would make a perfect Hell); others I did the okay work of preparing meals, and some I did the truly enjoyable work of daycaring the children.