Well, you don’t have to have ‘friends’ and you can make it private so that only people you actually know can read and talk to you. There are ways to have private convos.
My kids are on FB and I understand the privacy settings.
However, those privacy settings are no guarantee that your FB “friends” will not make your postings available to others.
Nonetheless, this should be a lesson to all of us and our kids, to be very careful as to what is posted on FB.