Dude, I am wondering how this tread is still going. It's underwear. Some men have perfectly good reasons to wear an undershirt. Others do not. Of all the things to hold really strong opinions about what others are doing I am slightly amazed this is getting so much attention and passion. In some other thread, men are talking about buttoning dinner jackets for God's sake and no one really seems fazed. Of course, we also live in a world where people with ostensibly good breeding and proper education call a neat vodka a Martini.
I despair. We live in the end times.
It's become rather like... "I wear Y-fronts, so everyone else must wear Y-fronts, Anyone who wears boxers or briefs is an uncouth evil smelly bastard!!!"