It probably makes us look like assholes when people compare that to rape. The same goes for 'meat is murder'. I mean, carnivores are technically murdering animals, but the word murder specifically refers to a human killing a human. If a bear mauls someone, we don't call it murder. It's kinda like using the word assassinate when referring to a car crash.
I think using strong words that are usually used to describe violence towards humans makes non-vegans have a knee jerk reaction and not want to relate to us, and just smothers the intention behind the message. Let people take baby steps into understand speciesist oppression and that animals have feelings before you start talking about them feeling deep emotions like being emotionally disturbed by being raped.
People don't think animals feel at all, let alone think they would care about being "raped".
People get defensive, and any chance you had of convincing them is lost; or You will end up in an argument about semantics, when you want to talk about oppression of animals.