Overall HP.
I don't think he was generally evil or so, indeed identified problems with excessive capitalism, but his proposed "cures" were questionable all too often.
The big flaw with Marx was that he was good at identifying problems and extremely short on developing detailed 'cures' to those problems. His later acolytes stepped into the breach with... um... mixed results, but those by and large can't be laid at the feet of Marx the man.
He identified a good system (capitalism) and decided that it was a problem.
It’s worth bearing in mind that Marx didn’t consider capitalism to be a problem in and of itself. He was actually surprisingly complementary of it in certain writings - he considered it a necessary stage in the upward progress of humanity that would soon be replaced by socialism (a further advance), a stance that marks him out from some other socialist thinkers of the time (Fourier) who regarded capitalism and its accoutrements (trade, investment) as bad in and of themselves.
You're right. That's why he supported Abraham Lincoln's war of aggression against the South.
The funny thing is that many of my issues with Marxism apply to dogmatic libertarianism. Especially when the utopian world view fails to provide an answer to a complicated event, rather than question the dogmatism, the approach is to undermine the necessity of the event even it requires going to extreme lengths to do so.
Sometimes war is unavoidable and in those cases you have to be able to fight it.
Marx supported the triumph of capitalism over the extractive slave economy of the Confederacy, because he thought it advanced on the road to his socialist utopia. His utopia was flawed, but it doesn't make the triumph of capitalism in this instance flawed.
The political culture of South was degenerate and diseased (the consequence of it needed to justify the continued existence and expansion of slavery as opposed to hand waving it away as a necessary evil like someone like Thomas Jefferson did many decades earlier); its economy was trapped in a backwards and atrophied state; its proportion of the population of the country in severe decline; and in spite of employing most of its people in agriculture it was still being out produced by the North even in that sector, thanks to its better technology, transportation and economic system.
The South was equivalent of East Germany or North Korea, a backwards and oppressive slave economy built on a slavish singular devotion to a misguided political force. How very ironic that Communism produced the exact same result that was supposed to be a relic of the past.
I will never understand or agree with the affinity that many Libertarians have for the Confederacy, as it undermines the message and communicates a seeming hypocrisy at the heart of the present Libertarian political movement (to the extent such exists). Ron Paul's embrace of neoconfederacy was largely that of political expedience, since Libertarianism is a rather small political niche and absorbing this was of mutual benefit. Paul got supporters and neoconfederates got to claim they really about freedom.
The problem is nothing about the South was libertarian. Its belief in state's rights was selective and only for convenience. Its slave system violated every tenet of a free market and was dependent on high levels of government support to be maintained. The necessities of maintaining the slave system dictated restrictions on the freedom of speech, religion, press and assembly. Slave societies, the history of the world over, are a story one of oppressive regime after another.
Yet people engage in this weird compartmentalization of "The south's oppression" as being something along the lines of "that was just the blacks, for everyone else it was a free society". Obviously, I don't need to say for whom this leap of logic most appealed to, but even on its own it is demonstrably false. Slave societies restrict the civil liberties and economic freedom of everyone who lives in them, because slave societies necessarily live on the constant knifes edge of threat of revolt, and thus the only way to maintain "domestic security" is to repress any thought, activity, or action that might intentionally or unintentionally trigger a servile insurrection.
No slave society can exist without the support and intervention of the government, which by definition means that the labor is being subsidized by the government. This crowds out wage labor, crowds out personal development and improvement, makes investment in competing models impossible and discourages education and encourages a drain of free labor to places where their skills will be rewarded. In any other situation, if you were to provide an example of "subsidized business model" that had these kinds of effect, Libertarians would rightly condemn it as the government created distortion that it is.
Libertarians need to recognize their is no such thing as an ideologically consistent and coherent libertarianism, that embraces, defends or supports the Confederacy.