Peeping As A Wacky Prank
In a curious break from reality, spying on someone who is naked in a movie is nearly always presented as hilarious good fun. If your landlord was watching you shower, you'd probably be upset. But if the gang from American Pie is watching two women get undressed, it's a goddamn party. Let's see how those crazy kids mess this up!
The "spying on women getting naked" trope is about as old as nudity. It was such a big part of the movie Porky's way back in 1981 (right after the Civil War) that they used an eye peeping through a hole as part of the poster art. If you need a reminder, that specific thing is also a big part of the movie Psycho. A good rule of thumb when it comes to interactions with women: Don't do anything that a serial killer who dresses like his mother would do.
Yet this same gag happens in literally three different American Pie movies, and maybe more, since I don't even think the company behind the American Pie movies knows how many exist at this point. You can also find it in The Girl Next Door, Hall Pass, I Love You Beth Cooper, and countless direct-to-video releases intended to make teenage boys laugh while jerking off. And it's so bizarre, because in any of those, just changing the score to horror movie tension music would turn the scene into nightmare fuel.