It says that with capitalism, humans cannot create a human community. It sees that any movement for a true community will oppose capitalist social order and social relationships all along the way. The motivating force will not come with a communist blue-print. It will come from living of proletarians creating a new social relation. The spirit of collective power, of a community of masters, is exactly the opposite of the democratic spirit.
Democracy drowns the individual in the choices of the majority.
It presumes that the individual choice is always hostile to the power of the masses. Thus democratic ideology creates the paranoia that everything contrary to its current formalism of process is the same as Stalinist dictatorship. The spirit of proletarian struggle can be seen when a group of partisans fan-out to defend a city. Each wing has the power to act alone in attacking capitalist forces. Each wing is just as willing to give in to the authority of the other proletarians when they indicate they know the terrain better.