Do you think it's possible for a guy my size (300lbs @18ish% bf) to maintain size and strength on a vegan diet without meat? Rhetorical question. God gave us incisors for a reason. Our Paleolithic ancestors, if they were good hunters, ate pounds upon pounds of meat per day. You do you, I'll do me.
That argument is actually pretty weak. Our incisors are pretty weak compared to some other herbivores in the world. If you study animals, you will discover that many fruit eating herbivores were given large incisors for biting in to hard fruits, not necessarily meats.
Our GI tracts are extremely too long to be intended for a diet very high in red meat consumption.
That said, I enjoy eating meats. There is a lot of evidence that supports both sides, and I find it amusing that people can't see both sides of the coin. The bottom line is, genetics, health etc should dictate the route we take. Some people go vegan because their cholesterol is through the roof otherwise, while others can eat red meat and never have an issue.
Lastly, early weight lifters consumed low to moderate protein, and they proved that a diet with moderate to low amounts of meat could still produce great results. Remember, this is pre-aas too.