Among other things, the author completely neglects to consider how the projects being open source contributes to their success in the first place. He also fails to consider the goodwill that it generates for the developer community and the ways in which that helps other aspects of Facebook's business (recruiting, hiring, culture).

Also, you'd think that someone talking about money would have some notion of how big a price differential "free" and "having to pay" is for a service, but that seems to have completely not been a consideration.