I agree in broad strokes with almost everything you say. I don't think adding rules is the correct way to build societies with some desired ethics.

That said, open source software licenses are extremely simple as far as contracts or licenses go. At least an order of magnitude shorter than closed source software EULAs, for example. What I see people advocating for is not tackling on additional complexity onto the existing licenses, but replacing the fundamental principles of existing licenses with new simple principles that slice the world into acceptable and unacceptable behavior in a better fashion.

Of course, licenses alone are not sufficient for change as you say. A lot of other social structures will indeed need to be built to change large scale behavior. That's a hard long slog.