Some men are truly naive and don't know that the clothing they are wearing is showing off their possessions, I am sure if you mentioned it to them, they would be embarrassed. In my local paper I look at the photos to see if anyone I know is pictured, and what functions have happened in the town. There were these group photos of some work function where this boofy looking bloke was there with his family jewels was quite prominent, he was circumcised by the way. He should have chosen different pants or a darker color.
I am very self conscious about my appearance and that goes for how my genitalia appears through my clothing. I make sure I am not showing too much, and will change if I am showing too much. As far as I am concerned when I meet people I want to be looked in the face not my groin and that region is for private consumption not the general public.