You clearly haven't been to a men's rugby club shower room, or a Japanese onsen where everyone has to strip off. Seeing other men's wieners is part of the deal. The Romans and Greeks were way more at peace with their bodies. Chill. Like, sure, the first time it's a bit embarrassing, but you get used to it. We've all got one. Humans were naked for most of our history. Wearing clothes is a recent thing.
If you're so triggered by seeing another man's member, some might say that says more about you tbh. Insecure? Jealous? We've all got one. What's the big deal anyway? It's just the human body.