Socialism, by definition, attempts to manage society in all its aspects, and in order to create the ideal it seeks to embody, it must necessarily control the actions of the individual members of the society. These individual members become essentially simply cogs in the machinery of socialist governance, and their individuality must be suppressed in order to ensure that the ideology of the socialist government can be fully implemented. As socialism moves towards a more perfect realisation, it necessarily moves away from the democratic forms which need a degree of individual liberty, and thus, we see the rise of totalitarianism result from a period in which socialism has been developing. The ideal of liberty is discarded, and even the ideal of equality, possibly subject to continued lip service, falls as a ruling elite takes charge of the society in the name of the mass of the people.
Sri Aurobindo notes: “Totalitarianism of some kind seems indeed to be the natural, almost inevitable destiny, at any rate the extreme and fullest outcome of Socialism or, more generally, of the collectivist idea and impulse. For the essence of Socialism, its justifying ideal, is the governance and strict organisation of the total life of the society as a whole and in detail by its own conscious reason and will for the best good and common interest of all, eliminating exploitation by individual or class, removing internal competition, haphazard confusion and waste, enforcing and perfecting coordination, assuring the best functioning and a sufficient life for all. If a democratic polity and machinery best assure such a working, as was thought at first, it is this that will be chosen and the result will be Social Democracy. That ideal still holds sway in northern Europe and it may there yet have a chance of proving that a successful collectivist rationalisation of society is quite possible. But if a non-democratic polity and machinery are found to serve the purpose better, then there is nothing inherently sacrosanct for the collectivist mind in the democratic ideal; it can be thrown on the rubbish-heap where so many other exploded sanctities have gone. Russian communism so discarded with contempt democratic liberty and attempted for a time to substitute for the democratic machine a new sovietic structure, but it has preserved the ideal of a proletarian equality for all in a classless society. Still its spirit is rigorous totalitarianism on the basis of the ‘dictatorship of the proletariat’, which amounts in fact to the dictatorship of the Communist party in the name or on behalf of the proletariate. Non-proletarian totalitarianism goes farther and discards democratic equality no less than democratic liberty; it preserves classes — for a time only, it may be, — but as a means of social functioning, not as a scale of superiority or a hierarchic order. Rationalisation is no longer the turn; its place is taken by revolutionary mysticism which seems to be the present drive of the Time Spirit.”
Sri Aurobindo, The Human Cycle: The Psychology of Social Development, Chapter 19, The Curve of the Rational Age, pp. 204-205