What little they did write in the Manifesto did plenty of damage all on its own, and it served as a step-by-step guide for most of history's failed communist states. (Particularly the bits of making "despotic inroads" on the existing systems)
I don't disagree, but I also think much has been lost in translation between 19th century phrases and language and conventions vs now. Context of the time was revolutions in the context of a mix of brutal 19th century monarchies/dictatorships, proto-capitalist/mostly agrarian economies, and brutal badly regulated industrial capitalisms.
The phrase "dictatorship of the proletariat" in particular has a very unfortunate history and ... interpretation.
