I think you're misconstruing what the author has said, as he does not appear to have "hostility to the open source movement", as he has several open sourced projects on his github.
Did he express discontent with a specific type of advocate? Yes. But he explained why, so it should be something you could understand by reading what he expressed.
He basically shares the same view as you: if you don't want to share your code, then it should be totally fine. There are people who do not agree with this, and this is where he draws a distinction.
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.
>I just totally don't understand this attitude. Code isn't money. I'm not diminishing you by reading your code.
I think the argument goes:
Then why is any code proprietary? If I'm interviewing at a company, I should be able to see that company's code prior to working there.
I also think a general issue is that practices such as this and employment agreements where the company owns any work you do off hours make it harder for people to jump from being employees to working for themselves (both in mindset and in practical ways).
Please see my response to @datalus below which addresses my thoughts on when I open source code.
Agreed, we all benefit from open source, I think it's almost impossible to avoid an open source tool at some point in your career now as a developer. I love Git and have a lot of respect for Github as a company. My intentions in my post was to address how people misuse such great platforms potentially.
Also, please see my response to @mafro below which addresses your final point.
"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."
Code is money. Some people are developing products not just frameworks. Some people are paid for developing open-source stuff while others do this as a hobby. It's a personal choice. Open-source is not the only way and it's not the best. There is still no open-source project that would match Photoshop, Windows, MS Office in quality.
Did he express discontent with a specific type of advocate? Yes. But he explained why, so it should be something you could understand by reading what he expressed.
He basically shares the same view as you: if you don't want to share your code, then it should be totally fine. There are people who do not agree with this, and this is where he draws a distinction.