@aral I think that there is a more nuanced discussion there.
The way you frame it leaves no space for licenses such as MIT, which are about sharing as well, but with different constraints and guarantees.
Yes, I know that licenses such as BSD/MIT allows one to close their alterations on derivative work. If that is a concern, then GPL is your friend.
Still, there are cases when the authors are perfectly fine with that, and still want to share their work. In these cases BSD/MIT make sense.
@rakoo MIT license is copyleft, and it is also a political stance. In my opinion, there are software who benefit from GPL and other software benefit from MIT. It is not a binary "GPL or bust" for me.
Also, caring about digital commons does not mean just the GPL. There are many options, unless of course you think that the BSDs are not a part of digital commons...
It is a political action that says "this is what I did with it, do it as you wish, if you want to contribute back, it is ok"
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