I find it interesting that he's commenting on things which he's never experienced. Theoretical concerns are something that one can address by actually speaking with people who have practical experience. Has he done any of that?
When speaking of various forms of non-monogamy...it ain't poly if you're just fucking around.
While polyamory, open relationships, and swinging are all distinctly different approaches to non-monogamy, they are not mutually exlusive. Folks can, and some do, engage in more than one of them at a time--and it's all good.