This may come as a surprise to many, but GPL is against my religion. As a Buddhist I cannot, in good conscience, release any of my code under GPL, or, for that matter, submit any improvements to someone else's GPL'd code.
While most of my software is free of charge and includes source code, none of it has ever been released under GPL. None of it ever will.
It has nothing to do with the most common argument about GPL being anti-business. I am not concerned about that.
The reason why I, as a Buddhist, cannot release any of my work under GPL is the stipulation that binds any future contributor to the code to make the source code to his/her modifications available to anyone who wants it.
As a Buddhist, I am free to tell anyone how to use my own work, but I can never impose on others what they should do with theirs.
To be faithful to my religious beliefs, I can do any of the following:
What I cannot do is allow others to modify my code and force them to release their own modifications in source code. Hence, I can neither release my software under GPL, nor can I add any improvements of my own to any code released under GPL by someone else.
Having said that, I am not telling anyone else not to release their own code under the terms of the GPL. I am just saying that I cannot do so because that would be against my religion.
I release most of my code under BSD license which allows others to distribute it with or without modifications, in source code or in binary.