Oh and australopithecus ate meat, this goes far beyond modern humans. This is why we got smart, because intelligence pays off far more for hunting than for foraging, particularly for an otherwise frail creature.
In terms of the last thing you said. You phrased it as "australopithecus ate meat"; it seems they predominantly were herbivorous according to wikipedia[2]. Which doesn't preclude eating meat, but could easily be misinterpreted from the way you put it.
[1] https://livinontheveg.com/wp-content/uploads/2017/02/compara... [2] https://en.wikipedia.org/wiki/Australopithecus#Diet
I didn't mean to imply that australopitecus was predominantly carnivorous, but I recently found out they had tools for hunting and/or cutting flesh, just to make a point that the trend started much earlier than homo sapiens.
Might come back with more links/thoughts later
Food has extremely strong cultural significance and a lot of people tie up their identity with it. I can understand that. If they feel that their diet is under attack they see it as life and death for their identity.
I imagine you've picked a side and will seek whatever information or studies suits you; everyone is doing that these days. It's anti-scientific.