I am not a wild swimmer myself, but DD is and she does it because she enjoys. When the family are down we go to a wild swimming millpool just off the Thames near Lechlade, no sewer outfalls above there.
All the family, except me, will swim in the sea nearly all year round. It is fun, exhilerating and other wild swimmers are good company, I am told. I grew up and learnt to swim in the tropics, I do not swim in unheated water anywhere in the UK, not even in the height of summer.
Just because one person doesn't like an activity, is no reason to despise those who do.
I would never go to a gym, but i full appreciaate others enjoy it, even though its pleasures elude me.