If you are some low level employee, certainly, the liability is too much.

But very higher level employees and Zuck himself? I would have to see actual proof of very secure lockout and segregation policies and procedures with zero exceptions or higher level administration access across the entire company to even have a chance to believe it. And that is way more effort and organizationally burdensome and costly than just trusting a few people to not be morons and be available when needed because you pay them enough money to not blab or give out access to others.