Take this hearsay as you like.

Someone I am intimate with left Facebook in the last month, in anger at the way senior management up to and including MZ first dismissed the severity of the problem of their platform being used to push propaganda during the election cycle.

And then stonewalled and foot dragged efforts to correct this. By the account I got the only incentive for action has been unflattering attention at the national press level.

This from someone with a personal relationship with Z.

Make of it what you will. The poison is real.