> his work is still an extreme pro-communist screed
Marx, for all intents and purposes, created what we today would consider "communism". That is, from a academic perspective, and not whatever goes as "communism" in American pop culture.
> the damage is not yet over, as some idiot somewhere will always be tempted to live off somebody else's money
The above is a terribly ironic criticism, considering how Ayn Rand lived out her life living off of the dime of the government.
> His work, in fact, led directly to tens of millions of deaths in 20th century
If we presuppose that any death, as a result of the actions of a state claiming to be using a given economic system, is attributed to said economic system we should be counting honestly. Every death caused by Capitalist countries, both domestically and abroad, should also be counted.
Every person that has ever starved to death under capitalism should be counted. Whether there's a direct shortage of food, or the person can't afford the food available, doesn't really matter. A person isn't receiving food when acting inside the system and thus died.
Then consider the imperialism carried out by these capitalist states. Millions upon millions of native inhabitants of Africa, South-East Asia, Southern America, and North America have been all but wiped out by capitalism.
What about WWII? Because in the of-cited number of "100 million killed by Communism" several wars are counted. In WWII a major contributor was the failure of the capitalistic system in Europe after WWI.
I could go on, but I think the point has been made.