@Walter Hinteler,
It isn't taking it out of context if the sentence means the same thing standing alone as it does when it is in its full context. In this case the intent or meaning of the sentence did not change when it was separated from the entire paragraph.
For comparison, when some took Limbaugh's "I want Obama to fail" line out of context and showed it as a stand alone sentence, the meaning was entirely different than what it was in context. Put the sentence into its proper context, however, and it clearly was intended to mean that he wanted Obama to fail in pushing through a destructive leftwing socialist agenda.
That was not the case with the line Sowell used from Marx's writing. The full context affirms that Marx intended the sentence exactly as Sowell used it.