I believe you are wrong. I believe good evidence shows that a diet of only milk and meat will cause death by scurvy. The fact that somebody once told you otherwise does not make it true. This is a big problem that many people won't face: accepting anecdotes uncritically does not constitute evidence. If you want to convince me that humans can survive on milk and meat, you're going to have to do much, much, much better than repeating a story somebody told you once. You're going to have to learn how to know things.