I think... ideally, the GPL wouldn't be necessary, we'd have a strong software commons, and people wouldn't take advantage of it to exploit the rest of us. That's not the world we live in, though, and I see the GPL as an attempt to bootstrap a commons in a world that cares for profit above nearly anything else.

Is it selfish? Perhaps, in a way. I'm sure there are some who genuinely value the freedoms granted by more permissive licenses for their own sake, and who are principled enough to never take advantage of that and lock up the results. You may be one of them, and I can respect that position. I'm willing to bet most of those who strongly avoid the GPL are not.