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

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.