I think the author makes the case. Obviously there is nothing wrong with just showing your code without further involvement, but from my perspective many people do it for completely wrong reasons.
I may be a selfish coder-for-hire, but my time is expensive and my tools are valuable. I only consider open sourcing my code when:
a) I want the project to grow and be seen by many eyes and I expect patches and improvements,
b) or I want somebody else to take over the project eventually - because I might find it useful in the future but currently don't have time to develop it any more.
Such projects, which are open source for selfish reasons, tend to flourish.
Projects which are put up on github or sourceforge or whatever kids these days use, just to get the free hosting or to be able to put on a resume "Leader of an open source project (and in fact the only contributor to it)" tend to be just noise (with some notable exceptions).
So, it's not about bashing people who don't engage the community, it's about telling them that if they want to have a successful and meaningful project, they should know it's a full time job.