https://www.researchgate.net/publication/358322559_Is_a_Plant-Based_Diet_Associated_with_Relationship_Aggression

Plant based diet has actually shown some relationship data with some forms of aggressiveness.

Study proposes normalize the data according to childhood trauma, but even then it would only show that plant based diet and omnivore diet have no differences.

And while there are also papers which relation eating meat qith aggressiveness. Most aggressiveness linked with diet is usually related to red meat consumption in excess. Not with all meat, neither with a balanced consumption of red meat.

Anyway, all those are barely noticeable. Not worth the benefits of people being able to chose their own diet.

As said the fundamental difference in philosophies, is the consideration of the existence of "animal rights" or not.

In a selfish tone, we concede all human, human rights because it's the path that leads to better live for one self. If you discriminate another human that human could have reasons to hurt you (legitimate reasons) It's proven that egalitarian societies work better. With animals this does not happen. Animal attitude towards humans is unchanged if we give them rights or not. It's not like a mosquito is going to stop bitting me because I consider it a first class citizen. Animal contribution towards my well-being will be the same, I eat them or not. From a practical point of view, giving animals rights achieve no goals neither for me or humanity as a whole. That's why I only concede humans rights, because giving human rights do make humans better, thus makes my life better.