Zuckerberg doesn’t have a control panel where he can move sliders all by himself, any change in weight on the algorithm has to be implemented by a whole bunch of people, any of whom could leak to the press.

It’s not guaranteed it would happen by any means but it’s definitely something that would factor into a decision. Broadly I agree with you though, normally I’d say “extraordinary claims require extraordinary evidence” but I’m increasingly convinced the extraordinary claim here would be that they aren’t manipulating things to benefit themselves in some way or another.