Serious question, cause I'm really curious.
I love the movie Kung Fu Hustle, just re-watched a bunch of it on cable and the 2nd time watching it, how many other movies it references is just crazy apparent. The Matrix, Spider-Man, Road Runner (a bit too obviously), I even caught a Kung Fu Panda reference I think. Almost everything in the movie had a purpose and was deliberate.
What was the purpose of the visible male asses in the film? I guess that could be a reference to sagging "fashion", but that's usually visible underwear. Is there anything specific the director was referencing with that or did he just think it was a good visual? I googled, and while there's reference to this a lot, I couldn't find an explanation.
There's one in the 2nd final scene right at the end as they pull away from the lollypop shop, and there's a reference where his fat friend (now a good guy working in the shop) says "pull your pants up" to a bunch of kids.