Maybe people using GPL only want their code to be used in other GPL projects and they want to improve the world in that way. For example I want people to reciprocate: if I give you some code, give back some code too.
But don't forget the LGPL, which lets GPL code to be used even inside proprietary one.
For some people, user freedom is a large chunk of the value.
Re:Is the GPL Really Declining?
by Thrillington on Thursday May 04, 2017 @01:28PM
(#14266815)
Extracting value through code is not an inherently positive moral exercise.
It may improve the world. From my perspective code that is built to extract value eventually attempts vendor lockin to create a long term revenue stream.
Code in itself isn't useful. You're not improving the world by writing code. You're improving the world with the impact that code can have and the value it can deliver.