UK is definitely on the American side of things in this. Lived here for a long time now and there's definitely a lot of that "oh no a child might see a nipple, how awful". But yeah, in Germany, Czech Republic, Slovakia, Poland, Spain, maybe even France - people would care a lot less. Especially in Czech Republic and Slovakia - you go to a public swimming pool, people just change in the open, children included, no one minds or cares.

(obviously that's just my own travel experience, I don't doubt there are places in all of those countries where that's not true)