I think it looks dumb too and every time I see a guy like that I make fun of him with my friends. Do you think it's a coincidence that the rise of this pant sagging thing coincided with the rise of the acceptance of the gay culture in mainstream media? I think it's related to homophobia. The last time that men actually pulled their pants up and wore them properly was the 1980s. In the 90s, when gayness was embraced by the media, men seemed to start sagging their pants. I think it's related. Gay guys always wear their clothes really nice and neat and it seems like this pant sagging thing is a rebellion to that. I know they say it comes from prison culture but we don't adopt all prison trends so why that one? I think it's a rebellion to the acceptance of gay culture.
I don't show them off but boxer short naturally rid higher than jeans so if the guy has a short shirt on or is stretching you will see them. For these guys who wear their jeans by their knees I have know idea I had the feel of it and I think it makes them look lie knobs.