The reasoning is, once you see a CEO installing loyal lieutenants. Who does not value conflicting, and opposing views. You know the company will loose the plot soon. With out any moderation from others I believe that FB will accelerate their disregard for their users while publicly communicating something else.
Fundamentally the Instagram founders and WhatsApp founders leaving is due to a values conflict with Zuckerberg and the culture at FB. My theory is there are the values they talk about and communicate externally, which is not congruent with what is practiced.
There was conflict due to these unspoken values and Zuckerberg took the easy way out. Install people loyal to him. This is a sign of weak leadership.
Edit:
It also seems like ego is getting the better of Z
“Severe cutbacks ordered by Mr. Zuckerberg in how much Instagram was promoted on the main Facebook platform”
Either that or instagram ads are not as profitable as FB?
Edit2: “That’s a shame, since that’s exactly what Facebook needs. Which is to say, people willing to challenge the groupthink that for too long included a stubborn resistance to admitting and addressing the company’s flaws.”
This is the biggest danger