Privacy vs. need for regulation is a continuous scale, and where on the scale we need to be with particular product heavily depends on the product itself.
Here's great twitter thread by Alex Stamos (ex-FB CSO) which does a great job of explaining it:
Expand the whole thread, it's worth it, but this is the crucial graph: the more amplification the particular product enables, the greater need for oversight and transparency there is. Policing 1:1 chats is totalitarianism and pointless. On the other end of the scale, allowing ads to be targeted and run in secret, without oversight and disclosure is very very dangerous.
Facebook operates on the whole range, but oversight and transparency needs to be separately calibrated for each level of amplification. It's not a one-size-fits-all solution.