I too worry about this aspect of Facebook so I tend to be silent observer on the platform. But like I mentioned, Facebook used WhatsApp as a backdoor entry into my phone to steal my list of contacts. And though they are not on my Facebook friend list, I now get emails informing me that I can friend them on FB if I wish. Creepy is the word that defines FB.
I also recall reading how a data mining company used Facebook data to influence the poll victories of Brexit and Trump.
No smoke without a fire.