The problem with the showers at the gym is that you’re not supposed to pee in them.
I’d feel badly if I peed in the shower at the gym. There are communal water drainage moats for all the stalls, and they swirl around the entire room before emptying into each corner. Along the same lines of not wanting to step in someone ELSE’s urine, I don’t think I’d like to be the cause of another person’s yellow-foot.
At home, it’s fair game. It’s my shower. I clean it. If you don’t like it, go shower at your own house.
Pools are a whole different issue.