OK if that's how were going to play it then fb isn't responsible if a friend, of their own volition, shares it. However if fb says "you shared it now WE can share it" is a whole other game.

Regulate Facebook. They lied and said they weren't intentionally playing with people's dopamine to grow themselves. They're lying now (in a roundabout way). They're always going to lie. Why will they always lie? Because there's no accountability.

Regulate them. Force their hand. That's the only way we can stop creeping further into dystopia. They won't do it on their own and at this point no one should be comfortable with their practices.