Here's the danger of making assumptions about people you don't know on the internet. As it happens, I not only read the manifesto, I was born and raised in the country that had the study of the discipline of "Scientific communism" a requirement for getting any higher education: http://en.wikipedia.org/wiki/Scientific_communism So I have a very good reason to assume that my background in both theory and practice of Marxist regimes is no less than yours. While one could have legitimate differences on the merits of teaching of Marx, it is obvious to any informed person that they were presented as the scientific basis for building new kind of society both in theory and in practice. Even if the theory was false and the practice made it degrade into dogmatic repetition of meaningless drivel, it was still presented as the scientific approach and meant to be so.