Sometimes that's true. Sometimes the right approach for a project still just getting off the ground is not letting people in for a while.
It's easier to realize a vision when you've already got something concrete to point to. Otherwise you often waste time arguing over what color to paint the shed.
Sometimes there is another team out there that knows a better method to determining what color to paint the shed. As an open source developer, you are more than welcome to disregard feedback regarding your code provided it is publicly available, but when you don't make it available, how can it be called open source?
It can't be. Until they make it available. Hence the verb usage of Open-sourced, an action they intend to do to the project. That is, they intend to change it from closed, and very private, to open.
It's easier to realize a vision when you've already got something concrete to point to. Otherwise you often waste time arguing over what color to paint the shed.