Capitalist states are also authoritarian. In fact all states are.

Frederick Engels, 1872, On Authority

Why do the anti-authoritarians not confine themselves to crying out against political authority, the state? All Socialists are agreed that the political state, and with it political authority, will disappear as a result of the coming social revolution, that is, that public functions will lose their political character and will be transformed into the simple administrative functions of watching over the true interests of society. But the anti-authoritarians demand that the political state be abolished at one stroke, even before the social conditions that gave birth to it have been destroyed. They demand that the first act of the social revolution shall be the abolition of authority. Have these gentlemen ever seen a revolution? A revolution is certainly the most authoritarian thing there is; it is the act whereby one part of the population imposes its will upon the other part by means of rifles, bayonets and cannon — authoritarian means, if such there be at all; and if the victorious party does not want to have fought in vain, it must maintain this rule by means of the terror which its arms inspire in the reactionists. Would the Paris Commune have lasted a single day if it had not made use of this authority of the armed people against the bourgeois? Should we not, on the contrary, reproach it for not having used it freely enough?

The Vietnamese state itself will tell you that it has not yet reached its end-goal of communism: the absence of social classes and withering away of the state.