Saying "giving everyone the right to share it" is contrary to the goal of having it be shared widely (aka adopted), is at least a gross oversimplification and at most an absurd statement.
Getting more adoption as part of proprietary software may or may not lead to more overall adoption. Bsd kernel vs linux kernel is a case for gpl leading to more adoption than permissive. GPL says "allow EVERYONE to share it." And in some cases, more people share it this way! Who would have guessed? And it can lead to more people contributing, because they know everyone will have the right to share their work. The fact that permissive code means it could be shared LESS, because it can't be part of software which makes sharing illegal, is kind of across purposes. I mean, if you just care about adoption, a lot of times, you might get more by keeping it completely proprietary and selling the copyright to a big company. Or you might get more by embedding it into worms and phishing emails and running a botnet.
I'm not writing a kernel. The fact remains that if I use the GPL, people will tell me that they can't use it because their legal department forbids it. Alternatively, using it requires approval from their legal team and that requires enough effort not to use my code.
This isn't some theory that you can weasel your way out of using examples. It's based on real experiences I've had.
