I'm disgusted by that, too, because then I'm standing in a pool of my own urine and its soaking into my swim trunks and ew.
The fact that the ocean is full of fish pee changes nothing about this for me.
I think it's gross and I do not do it. I don't like the idea that my feet are touching the bottom of the shower where my pee just was seconds ago. Gives me the shivers even now just from imagining it. Sounds like someone's fetish. Not in my house.