you can work at a charity and still be paid, even though the "non-profit" moniker can confuse layman.

> I release my code under the GPL for selfish reasons: I want others to be able to improve it, and me to be able to take advantage of their improvements.

I suppose that metphor depends on what you think of community efforts. Like say, sharing a food recipe or a workout routine. I see see the framing as "giving it away". Even if your endgoal is an ultimately selfish search of "better recipe/routine to use".