Then, just like television is not responsible for TV addicts, Facebook may not be responsible for the susceptibility of people to believe and share fake news.
Why should Facebook be responsible? Do we really need to "protect" people by preventing them from reading tabloid magazines?
I think the problem to address should be improving education. If you are well educated it would take a much more elaborate effort to trick you. It's still possible, e.g: race baiting and conspiracy theories have become a thing lately.