I agree with the OP's statement that if you didn't contribute to the code (and you didn't pay for it, etc), you shouldn't have a say in whether or not the software is open-sourced.
However, I think that unless the programmer has a good reason not to open source something, they should default to releasing it. I have a couple reasons for this.
One, it's impossible to predict what other programmers will or will not find useful. I have lots of code on GitHub that is not in any sense production ready. I don't care -- maybe someone will find it helpful.
Two, as I said in my previous comment, whether we want to admit it or not, we're all using and benefiting from open source software all the time. GitHub -- the site we're arguing over -- would never have been possible without Git. I feel indebted to the people who came before me and made all this possible, and I don't understand people who react to the subtle pressures to contribute with hostility.
The person at the bottom of this comment list said "I have about 6-7 repos in GitHub...all private. I will never give that out in a link. I don't mind you looking at it in front of me, but I'm not giving anyone access to it." I just totally don't understand this attitude. Code isn't money. I'm not diminishing you by reading your code. And, as the last 30 years of blazing success in open source software has shown, the benefits of the open-source ecosystem are far from abstract. They're the foundation of everything we do.