This is the main reason I cancelled my FB account some years ago now. I had a couple good mates working in IT security and none of them were on FB, it was a big red flag for me.
I'm sick of needing FB to claim a lot of good deals at pubs and restaurants (like us on facebook and get a free blah blah blah). It is discriminating against people who don't have facebook, its not fair. /dollies out pram