I think they went for the rape and animal killing precisely because gore doesn't have much effect on people anymore. Back in the day gore was shocking. As people became desensitized to it horror movies that wanted to stand out needed something new.
Back in 1980,gore was a big scare thing in films.
Now-they throw blood and guts around like confetti-it aint scary no more.
You had crap like 2000 MANIACS and low budget s**t at drive ins...and George Romero,of course-but cannibalism wasnt prevelant in film like it is now.Back in 1980-it was still shocking. I just dont like the idea of killing animals for a f**king movie.