> Developers are users.
Developers are users, but so are non-developers.
The question of whether developers should be able to restrict freedom of non-developers is the question of whether some users should be able to restrict the freedom of other users. This is an ethical (subjective) question.
Put another way, should landowners be allowed the freedom of having serfs or indentured servants? Not allowing them to do so is restricting the freedom of some people (the freedom to own serfs). But allowing them to do so is restricting the freedom of other people (the freedom to be... well, free human beings).
As a society, we believe restricting the freedom to be human beings is ethically abhorrent, so we have no qualms (anymore) about restricting people's freedom to own serfs.
Maybe you see non-free software as ethically abhorrent, the way slavery is, maybe you don't. But that is the axiom that the free software movement (and the GPL) is based on - to understand free software, you have to understand that principle, even if you disagree with it.