It seems to me that this article takes some points of Marx's theories that are at this point relatively well-trod ground by people who actually study marx and connects them to specific historical events happening right now. I'd suspect the author is taking from some condensed version of say Capital or the communist manifesto, or more likely, a condensed treatment of one of those works.
I've always thought that Marx was very much an enlightenment thinker and was fully grounded in the events of Europe, both politically, socially, and economically, and reason was one of the core ideals of enlightenment thought--making man the center of history.
I think that Marx attempting to "turn hegel on his head" and ground historical processes in the material instead of some zeitgeist was a pretty important shift. That being said, you're right, compared to Adam Smith, he absolutely was far more based on reason, but that was probably due to his environment as much as anything.
Also, this it's in the Rolling Stone.... hardly a peer reviewed journal. I think we can forgive him not giving us specific citations.