A communist society, loosely defined, is basically a society where a gift economy is the norm ("from each according to his ability, to each according to his needs"). In such a system, people freely contribute to the well-being of the community without expecting direct rewards for it and anyone is free to enjoy the fruits of the labor of the community as a whole.

For such a society to work, you need high trust between all the parties involved. Every member of the community must be able to trust every other member. Trust is needed because there's always the threat of a free-rider enjoying himself at the expense of others while contributing nothing, and if such behavior becomes widespread your community will collapse.

There are a handful of examples that communists love to give as proof of the viability non-authoritarian communist societies: primitive communism (the way hunter-gathering tribesmen work together), Kibbutzim, the Amish, the Paris Commune, and Catalonia. I'm no communist, but I'll add another: nuclear families. Now, if all these examples are meant to work, they need to be societies united by a sense of trust and some common ground. In the case of primitive communism and nuclear families, it's kin altruism. In the case of Kibbutzim and the Amish, a common religion. In the case of the Paris Commune and Catalonia, a war enemy to unite against.

Now, if you'll notice, none of these common grounds are either scalable nor sustainable. You can't treat a stranger as if he were as close to you as a family member - no matter how much you've been inculcated to consider him and everybody else a "comrade". Religion produces as much unity between its believers as it produces conflict between believers and unbelievers, so it's untenable to use religion as a common ground in our religiously heterogeneous modern societies - most communists are atheists, anyway, and they have always been notoriously anti-religious (if there's one thing you'll see both Bakunin and Lenin agreeing with, it's this). And finally, as for war... well, who wants to live in a state of perpetual war? But it's no coincidence that Marxists preach the doctrine of class struggle and Trotsky desired a perpetual revolution for socialism to work, their goal was to provide a way of continually stoking the fire of the people, as to furnish them always the passion of the revolutionary.

The problem of Communism as a political movement is that it has no way of generating the scalable and sustainable level of trust needed for their goals. But they try. The totalitarianism that almost inevitably always emerges is always as a means to trying to enforce trust that wouldn't normally emerge in the large-scale societies that communist dictators try to manage. It may sound paradoxical to enforce trust by sowing distrust, but it's precisely what has always been done. Since there's no family or religion to appeal to, there must always be the threat of the "class enemy" for the "comrades" to remain united. If you're with us, you're a comrade - if you're not with us, you're a fascist/capitalist/reactionary/counterrevolutionary/kulak/what have you. Witch-hunts are always inevitably present in the communism program, because communism can't survive otherwise. It's not an exclusive feature of Marxism-Leninism and derivates - you'll find this behavior even [if not specially] in anarchist communities.

In conclusion, communism in the loose sense isn't necessarily authoritarian. Then again, those examples of communism hardly ever are the kind of society that communists really want to accomplish. Communism, as the secular and cosmopolitan political movement propounded by communists in general, will always have to recourse to authoritarianism in order to stay afloat. If not authoritarianism by the rule of a vanguard minority, then authoritarianism by Orwellian groupthink it will be. And hey, at least the latter is decentralized!

A communist society, loosely defined, is basically a society where a gift economy is the norm ("from each according to his ability, to each according to his needs"). In such a system, people freely contribute to the well-being of the community without expecting direct rewards for it and anyone is free to enjoy the fruits of the labor of the community as a whole.

For such a society to work, you need high trust between all the parties involved. Every member of the community must be able to trust every other member. Trust is needed because there's always the threat of a free-rider enjoying himself at the expense of others while contributing nothing, and if such behavior becomes widespread your community will collapse.

There are a handful of examples that communists love to give as proof of the viability non-authoritarian communist societies: primitive communism (the way hunter-gathering tribesmen work together), Kibbutzim, the Amish, the Paris Commune, and Catalonia. I'm no communist, but I'll add another: nuclear families. Now, if all these examples are meant to work, they need to be societies united by a sense of trust and some common ground. In the case of primitive communism and nuclear families, it's kin altruism. In the case of Kibbutzim and the Amish, a common religion. In the case of the Paris Commune and Catalonia, a war enemy to unite against.

Now, if you'll notice, none of these common grounds are either scalable nor sustainable. You can't treat a stranger as if he were as close to you as a family member - no matter how much you've been inculcated to consider him and everybody else a "comrade". Religion produces as much unity between its believers as it produces conflict between believers and unbelievers, so it's untenable to use religion as a common ground in our religiously heterogeneous modern societies - most communists are atheists, anyway, and they have always been notoriously anti-religious (if there's one thing you'll see both Bakunin and Lenin agreeing with, it's this). And finally, as for war... well, who wants to live in a state of perpetual war? But it's no coincidence that Marxists preach the doctrine of class struggle and Trotsky desired a perpetual revolution for socialism to work, their goal was to provide a way of continually stoking the fire of the people, as to furnish them always the passion of the revolutionary.

The problem of Communism as a political movement is that it has no way of generating the scalable and sustainable level of trust needed for their goals. But they try. The totalitarianism that almost inevitably always emerges is always as a means to trying to enforce trust that wouldn't normally emerge in the large-scale societies that communist dictators try to manage. It may sound paradoxical to enforce trust by sowing distrust, but it's precisely what has always been done. "Mass movements can rise and spread without belief in a god, but never without a belief in a devil." Since there's no family or religion to appeal to, there must always be the threat of the "class enemy" for the "comrades" to remain united. If you're with us, you're a comrade - if you're not with us, you're a fascist/capitalist/reactionary/counterrevolutionary/kulak/what have you. Witch-hunts are always inevitably present in the communism program, because communism can't survive otherwise. It's not an exclusive feature of Marxism-Leninism and derivates - you'll find this behavior even [if not specially] in anarchist communities.

In conclusion, communism in the loose sense isn't necessarily authoritarian. Then again, those examples of communism hardly ever are the kind of society that communists really want to accomplish. Communism, as the secular and cosmopolitan political movement propounded by communists in general, will always have to recourse to authoritarianism in order to stay afloat. If not authoritarianism by the rule of a vanguard minority, then authoritarianism by Orwellian groupthink it will be. And hey, at least the latter is decentralized!