Fun fact: the shape of human teeth debunks your "fact". Bite on your tongue using your molars, notice that they have points (unless you have ground them down), an adaptation completely unnecessary for herbivores as their teeth grind plant matter so that it is easy to digest (thus herbivores have rounded molars), were as sharp teeth are needed for dealing with meat, hence; if we were herbivores we would never have started eating meat as we wouldn't have been able to chew it.

Fun fact: the presence of both large and small intestines debunks your "fact" as only one is needed for herbivores, while the other is needed only for processing meat, hence; if we were herbivores we would never have started eating meat because we couldn't properly digest it.

Fun fact: you are wrong.