Marx and Engels are the founders of modern ("post-utopian") socialism, every branch of socialist thought applies their ideas in one way or another. Since communism is a classless and stateless society, it makes no sense to have "extremely high faith in government". So-called "Communist States" can be considered as such insofar as their leaders are indeed socialists/communists of a certain type, but the system they are the head of is not. This was made clear as early as Lenin, where the aim of socialism had to be temporarily abandoned because of the Civil War and the lack of a solid economic base in Russia. Ultimately, after Stalin's takeover, it was pretty much abandoned; even if the socialist political rethoric remained in the everyday USSR, there was nothing tangible backing it.
As Chomsky once said, two countries benefitted from calling the USSR "communist", the United States and the Soviet Union.