If I really think about it, I have seen what you are talking about in bathrooms — when I saw several men standing at the urinals. But I don’t think I spread my legs when urinating. I think I just stand there and pee as if I was standing anywhere else. Maybe some (maybe a lot of) men feel they have better balance and aim if their legs are farther apart. But to be honest with you, I’m not really 100% sure why some (or many) men do this. I never really thought about it much. Maybe I will me more observant in the future now that I know someone is asking about it. Maybe they do it so they don’t pee on their feet?