Argument
Eating meat helped us evolve
It doesn’t matter if it did, because we live in a very different world and different things today will make us evolve other than eating meat. Also, that something helped us evolve doesn’t mean that such behaviour is ethical or acceptable today. Early homo sapiens used rape as a strategy for gene-promotion when they could not get access to consensual sex. This helped the human species evolve to where we are today, we cannot then say that sexual violence is in any way acceptable.
In addition, most scientists agree that it wasn’t meat, but cooking foods, that made our brains evolve. This would explain why we’re the smartest animals and the only animals that cook, while other more carnivorous animals like cats are less intelligent than us. The hypothesis is that cooking allowed humans to get more energy from the same volume of food, and to spend less time chewing, which meant this extra energy helped fuel brain growth.