My little take on this is that, as guys, we're already more open about peeing. We've grown up going in pretty open places and standing in close proximity to others at the urinals. While women on the other hand mostly go behind closed doors with only their close friends for company every now and then.
They're also far more shielded (if that's the right word) when they go, making it very hard to actually see anything making the act a mystery to us guys. Consequently it gets our minds wandering and we want to see what goes on and so fuel our curiosity!
As soon as you're part of such an