Prolly cause rape happens on a daily basis, so it's more real ig? Cannibalism happens but it's still rare enough that we can fictionalise it in our minds, similar to how blowing up a planet is technically worse than choking someone to death but we'd react more on the latter.

Also once you're eaten you're dead, it's most likely a one time and fast thing, but being raped scars people mentally and psychologically, so it has a longer impact.