You realize the person who you accuse of having a "very simplistic view of capitalism" (the author) has been studying economics for most of his life and won a Nobel Prize for it? Currently a professor of economics at MIT? Etc...
One could argue the same about Paul Krugman.
And yes, one could and should argue the same about Paul Krugman. Of course it's possible that someone like Solow or Krugman is terribly wrong, but barring traumatic brain injury or something it's absurd to suggest that either is wrong on account of not understanding basic economics.
... Of course it's possible that Solow or Krugman understands something very well but then chooses to present an oversimplified version (for honourable reasons, like not intimidating their readers; or dishonourable ones, like wanting to hide something that works against their arguments). If that is what you were suggesting -- not "Solow's understanding of capitalism is simplistic" but "Solow probably has a sophisticated understanding of capitalism but is presenting a simplistic version, and a better one would invalidate what he says" -- then indeed pointing out that all the evidence suggests he's an extremely skilled economist isn't to the point. But what's wrong with it still isn't that it's "ad hominem".
There are plenty of eminent CS prof's that couldn't push a HellloWorld to Heroku, or competently perform entry level software development tasks.
Like the SE vs CS divide, "job creators" disagree with academic economists on the axioms of "basic economics".