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"Since we've not used our teeth much in the manner since the Stone Age, it's logical to assume that evolution would reflect the canine's increasing obselesence." - Skylance
Actually, evolution doesn't just do away with things that aren't used, unless the thing in question leads to early death. Human canine teeth would only get smaller if that made people more attractive sexually, or if big canine teeth cause people to die young.
Anyway, I know your point was that the purpose of canines isn't to chew through meat. It's just a slippery slope to use "evolution" as evidence for either side of what is really a moral issue. Choosing to eat meat or choosing to eat vegetables at this stage has zero to do with cause or effect of human evolution, unless one of the two makes people more fertile or more likely to die young.