If you're a maintainer and reciprocity is an important value to you, and you think that people who don't give back are freeloading, then why did you specificall

If you're a maintainer and reciprocity is an important value to you, and you think that people who don't give back are freeloading, then why did you specifically choose not to use a GPL license for your project? Your point about the gap between the words of a license and an ethical expectation is well taken. But why put that gap there at all? It's going out of your way to make sure that people have the choice to screw you.