No communist societies have ever been able to feed themselves - from the Pilgrims, to the USSR, to Jamestown, to the kibbutzen, to North Korea. Voluntary or coercive, the results are the same.
If this is Walter Bright creator of D, I must say I'm in awe.
Nonetheless, I agree with you 100%. It doesn't matter what form it takes. Majority of my millennial peers refuse to even accept that socialism leads to the inevitable outcome that is communism and that it is an evil that would deprive all of us of our individual liberties to a point where all human decency will be lost.
The great thing about a free market country is people can form workers' collectives if they want to. The only thing is they can neither force anyone to join nor prevent anyone from leaving.
Many such have been formed over the years in the US, and they've all collapsed.
Indeed a free market allows for workers to voluntarily unionise but seldom is it the case that members are free to leave at will. Any form of collectivism yields the loss of personal liberty and loss of property rights(members cannot opt out of perpetual membership fees). It doesn't help that most union leaders are disingenuous actors who exhibit acidic levels of corruption only comparable to that of majority of government bureaucrats.
There have been a lot of communistic societies over the years so I would be cautious about declaring them all unable to feed themselves. Having said this the only exception I can think of are the Doukobors [1].