Here is an omnivore trying to debunk vegan logic by using at least 3 different fallacies in abundance.
Those fallacies are hasty generalizations, ad hominem, and the good ol' naturalistic fallacy. I would spend some time rebutting the arguments more systematically; however, it is just so obviously not worth anyone's time.
I earnestly wish there were more omnivores out there who could propose good arguments for their side. It really would make the whole discussion more interesting.