I'm sorry, I can't agree with you at all on this @Emilia42
@Annina3 is in a completely different situation than you. She is a woman hosting by herself in a shared property. You are not.
I am in the same situation and would be highly uncomfortable if a sole male guest messaged me multiple times about issues not relating to my listing, called me and tried to friend me on FB.
I have never had a guest do that in over three years of hosting and having had hundreds of guests stay.
And I have never searched for a host or a guest on social media.
At the end of the day, as hosts, particularly as a woman hosting by herself, in a shared property situation, we need to be comfortable about hosting a guest and if we are not and want to cancel as a result because of safety concerns, we should be able to, without being taken to task by other hosts.
Do you send your guests friend requests on FB and call them before their stay?