Marxism is not really what I would pick to talk about Karl Popper and falsifiability... his writings on politics are pretty much a side-act. I am guessing the author was recently reading some of Karl Popper's more political writings. I would have picked psychoanalysis.
It's important to remember that in the '20s, Marxism was presented as a scientific theory, that it described a logical, teleological process by which human society could be perfected. This was the Popper's later great white whale. Ask George Soros!
The irony is that the standard methods of hypothesis testing which are often used to test statistical theories, including quantum mechanics, is based on reasoning with strong parallels to Popper's theory of falsifiability.
It is worth noting that Popper's theory is itself false. Real scientists do not simply throw away a theory because it is proven false. Good theories are hard to find. And a false theory may still be a useful approximation!
I agree that the Marxist part at the end disrupts the flow of the article. The article would have been better served if it kept within a financial analysis context.