Facebook is just full of scam and spam.
And it feels like nothing is being done about it...
For something like this you can only have a separate department that takes care of such scams and spams.
In the end it can also cast a bad light on the real company if people are scammed by fakes or are provided with false information.
It is how social media works. Two years ago, Facebook implemented new policies which cause to massive bans on many farm accounts. They required more steps to create a valid account for using. It is their efforts to eliminate farm accounts but it is not enough.
Spam is still there and on Facebook, you can see many bot messages to shill projects or to attack other projects. Scam is another issue that they can not control. They have features for page admins to hide scam messages, delete or report such ones.
However, people should prepare enough knowledge, read more, being more careful when they are on social media. In the end, they have to protect themselves from scammers, not Facebook, not any forum, not any social media platform, not any chat platform.