Well, I saw a sign that said "1/3 of people who stand here won't wash their hands". So, logically, if I don't then the odds that the people who cook my food will goes up.
But I don't really think cannibalism is like washing hands, though, since failing to wash hands can be directly harmful (well, not quite directly, but eh?). I think it's more like homosexuality and child pornography: cultural taboos.