Seems plain nuts to me. A good few years back a friend of mine who is a kamikaze about these things — he's the kind of guy that will dive into a lake in the high Alps that is basically melted snow — suggested we go for a New Year's Day swim in the Med. I just said to him, “Now why would I want to do that?”.
Nothing to do with social media, by the way. He is not on any social media that I know of. He just likes setting himself these physical challenges. I really don't.
I used to enjoy swimming in the Med in the months of June (that's best, before the hordes have arrived), July and August. Gave up because I'm not a good swimmer, never have been, and in my fifties I started cramping up when I was well out of my depth. I thought, “OK, that's it, your time's up.”
I always swim on my own, by the way. As I did when I used to run regularly.