"Engagement" is the "paper clip maximizer"[1] of the modern software industry, or more generally an example of "instrumental convergence."
Optimizing engagement without regard for negative externalities is a catastrophic ethical failure of the major players in the software industry, and we are finally seeing a backlash both from mainstream advertisers and widespread public outcry.
[1] https://en.wikipedia.org/wiki/Instrumental_convergence#Paper...