PS. I think there's also another aspect that made me like the image: the dying per se. A lot of open source projects are simply going to die, aren't they, and you don't want that as the author/maintainer, it's a part of your life after all. So the question very much becomes, it's either that project is going to die (with that part of me) or I'm going to protect it.
Users who don't have experience leading projects may not realize that this dying happens, they may only ever see surviving projects.
Now of course a surviving project that is also friendly is the best, no doubt about that, but the question how to achieve this is going to be partially independent. (The cowboy image may be more fitting for the fact that some projects die, and less fitting for how you achieve for it not to die.)
Users who don't have experience leading projects may not realize that this dying happens, they may only ever see surviving projects.
Now of course a surviving project that is also friendly is the best, no doubt about that, but the question how to achieve this is going to be partially independent. (The cowboy image may be more fitting for the fact that some projects die, and less fitting for how you achieve for it not to die.)