I just find it so absurd that it's funny.
I was maybe 20 when I saw the original. I was sharing with my bro and his wife and bro got the tape - yeah way back then. His wife went to bed and we stayed up drinking beers and laughing. The rape scene, though, I still remember it. yeah it was absurd, but I think my reaction to it was a bit primordial, like when a guy reacts to a fictional character having his balls sliced off.