Why not? I remember long time ago they blocked and de-ranked posts with urls to competitive products.

And I don't see anything illegal here. Facebook.com is a private website of Mark and stakeholders, they can do whatever they want on their territory (if it's legal). As much as you can do on your backyard.

Ethics is a different topic, but it's perfectly legal.

I agree, although there's another side to "patently stupid ideas", which is that outlandish (yet true) happenings are minimized.

Like if someone said "facebook tracks you everywhere you go" or "your phone is listening to you" or "your television watches everything you watch" it would be shrugged off.

If Facebook provided an explanation, the individual affected might be less prone to speculation.

Similar with job interviews these days. We decided not to move forward, but we can't provide any feedback or tell you why.

Looking forward to the day that Google, FB and Twitter are classified as public-utilities

It sounds like the people are the problem, not the platform. If anything things could be much worse without the moderation that does take place, and security.