Capitalism isn't rightist. It's just not leftist. Libertarians and Republicans agree on something, that doesn't mean it's a right-wing thing. Libertarians and leftists agree on some things also, those things cannot be considered exclusively leftist. A google search for "libertarian intellecutals" yeilds 437,000 hits. Stick that up your ass.
I'm a capitalist and I've read the Communist Manifesto. I haven't read Das Kapital as I haven't found a free version of it as I have the Manifesto and various free-market economics books, but I've heard numerous of the ideas contained within.
From what I've read of Marx, I think he misidentified the oppressor class. It's not the owners of the means of production that are exploiting, it's the owners of the means of destruction (the government). The bigtime capitalists happen to be in bed with the government, so while some of the big businessmen are certainly bad, they aren't bad as a class of people. Agorist class theory (
http://www.agorism.info/AgoristClassTheory.pdf) is demonstrably superior to Marxist class theory as illustrated in the PDF I just linked to.