I think the important thing is just the repulsion to the idea of cannibalism. You wouldn't think at a party about trying to drug someone so you could eat them, just the thought is horrifying. Literally the only situation it'd come to your mind as a possibility is one of the most desperate times.

That's how terrible rape as a concept should be. Literally bordering on psyche-breaking. Doesn't matter how similar the concepts are, it's our reactions to the concepts that matters.