Billions of users. I would imagine it is the entire spectrum of political and cultural opinions. Pro-live/Pro-choice. Religious/Atheist. Traditional/Multicultural.
I asked a question that it seems you've answered with a question. This is the Internet, so the only real "rules" are related to the physical limitations of the hardware in use. As is demonstrated in the article, other rules are more subjective in nature.
Yes, there are things more dangerous than someone who views themselves as objective while sanctimoniously berating other people for having "biased" views. I can name a great many.
Some may also be much more financially sound to back up their talk with resignations or other actions if they feel strongly that their employer does things that don't sit well with them.
But if they resign they would lose the six figure income and also any influence with future censorship battles at Facebook. Better to stay in, wipe your tears with dollar bills and keep the pressure alive. Zuckerberg will give up at some point.
This playbook is depressingly familiar around the world now. Relentless constant pressure to delegitimise institutions at every possible opportunity. Day after day. Week after week. Month after month.
Just a few recent examples. UK with Dominic Cummings, Australia with the fires, India with Hindu hysteria, US with.. well everything.