Because the last decade has shown the rather terrible consequences of private, proprietary and profit-driven networks like Twitter and Meta's various crap becoming de facto part of the common infrastructure of public life. A lot of public transit services publish service updates on Twitter. Most politicians have a Twitter presence. Many restaurants and small businesses don't even have websites anymore - just Facebook pages.

We want to stop exploitative for-profit entities from furthering their stranglehold on essential parts of everyday life. Nobody should be forced against their will to use crap like Facebook or Twitter, and that means advancing viable alternatives to those platforms that can fill the role they do in the internet era. If the "digital town square" idea is to live on, it should be as a commons like an actual town square, not a publicly-traded company or a billionaire's personal cult compound.