Platinum Games' Shigenori Nishikawa explains that the goal for the development team in Japan was to make the game over-the-top, but not to "ever aim to get laughs." He points to the first showing of the signpost-in-head maneuver, which was seen as "mean-spirited" and "left a bad taste" in Japanese mouths. When foreigners caught a glimpse, however, they were laughing it up, so Platinum Games decided to keep it in.
Nishikawa further explains the gap between the Japanese and us in the West, saying he's never "heard of a Japanese comedian think of some kind of gag that will get laughs overseas and have it actually work out." Well, whether it was intentional or not, Nishikawa did get one thing right about us: We love to laugh at fat people in weird outfits.