Likewise, a Gmail user is free to move to another email provider (there are large ones, unlikely to have deliverability issues), or run his own (a tricky enterprise, to be sure).
FWIW, I am concerned that democratic rule has its own failure modes, which need to be addressed when designing a system. Do 50.000001% of users really get to permaban another user? Are there any actions which require a higher threshold, or multiple votes over time, or which are permanently forbidden? The U.S. Constitution has the advantage of a Bill of Rights, whose status has so far prevented the outright abrogation of any of them, even if some of them have come under quite a bit of pressure (the First, the Second, the Ninth & Tenth leap immediately to my mind).
Just saying, 'the will of the majority controls' is a recipe for mob rule — which is exactly what 'democracy' means.