You're taking a highly subjective view and presenting it as fact. That Facebook is a "socially beneficial organization" is extremely debatable. I would argue that Facebook has actually had a detrimental effect on social cohesion.
In contrast, governments are violent organizations specialize in coercion. Governments extract their revenue by force or threat of force and use their revenue to fund institutions and projects that people would not pay for voluntarily. Governments maintain power by direct force (police and military), by deceit and misinformation (control of the money supply, compulsory education), by monopolizing necessary institutions and services (dispute resolution, security), and by appealing to people's greed and envy. It is nearly impossible to opt out of government services, especially in the sense of not paying for them (taxes).