If you have never contributed to a properly managed GPL codebase, you might be surprised the kinds of things you will be asked to do. More it the point, it most certainly isn't a right that you can contribute however you want to whatever project you want. Projects have constraints. Some people can _never_ contribute to Emacs because of the other code bases they work on (e.g. Chez Scheme). If you happen to be one of the folks who can, then in a sense, it is a privilege that reflects your freedom from other constraints.