On a related note, Facebook makes it so difficult to unlike things, unfriend people, and opt-out of information from individual advertisers. It's obviously hostile design aimed at making it as hard as possible to reduce your advertising value to them.
What Facebook is doing might not be illegal, but I think what they are doing is more unethical than many felonies. The people in charge of these decisions are getting wealthy from them, and they are never going to face consequences for their actions, which is a real shame.