His comment doesn't imply that he doesn't believe in contributing, he just says that they don't have resources for it (currently). I bet the situation is same for many startups, which struggle in finding profitability.
Agreed. Most of the vitriol in the responses focus on the tone of the attitude of "If you don't like our conditions, you don't belong in the tech team and should leave." There's little of note here wrt. open source.
I agree, for the most part. Not every setup can be open sourced, and not everybody has the capacity to contribute frequently. I lead a small tech team of 4, and we are usually pretty busy. When we're using an open-source tool that we find a bug in or need additional functionality for, I do encourage the team to submit a pull request to the source so the world at large can benefit. At this stage in our company's growth, though, it's not realistic for us to dedicate large chunks of time to random open-source projects.