This is an enormously broad question that really demands a course in social psychology. Let me use this opportunity to talk about human beings in general.
The nazi-vegans: the first problem
In the late 2000s, I noticed a fantastic trend: people who had been eating chicken wings for breakfast the day before suddenly woke up in love with animals. They went vegan without passing through vegetarianism, and like anyone who swings from absolute zero to the heat of hell, they started making a huge racket, silencing everyone and shouting that eating animals makes you Satan's spawn.
I called them "nazi-vegans" at the time, and it seems I wasn't the only one to coin the term because years later the word went mainstream.
I was seriously furious with these people, and I still am. Since childhood I endured every kind of bullying for my vegetarian choice — it wasn't fashionable, so it was me against everyone — and I always defended myself trying not to tell the conservative idiots insulting me that the problem wasn't me, but them.
Then these four newcomers, high on novelty and who were drinking calf blood until yesterday, start proclaiming themselves superior to everyone and ruin the veg cause for me. For me, it's serious business: my planet is at stake.
Food as identity: the second problem
For an omnivorous species that can virtually eat anything, what a human group chooses to eat tells us more about the group than about the food itself.
Omnivore = we can eat whatever we want. It does not mean = we must eat a bit of everything. This is not semantic fussiness. It's a fundamental difference.
In the West, an extreme food culture has developed: the culture of meat. People are convinced it's "natural" to eat meat two to five times a week. For a sociologist, the word "natural" is an indicator of cultural artifice and unconscious manipulation.
Westerners are blind to meat. It's become a commodity for them, like wheat. If meat defines your culture, it also defines you. It structures your ego. Remove meat, and the stage collapses.
"Meat is narrative" — Jonathan Safran Foer. And he's right.
Cognitive dissonance
Suppose you're hyper-rational. It's only a matter of time before you start connecting the dots and seeing how Western meat consumption is irrational. Stupid. Because it's not optimal for our species. Because it's the second leading cause of pollution and desertification. Because it generates antibiotic resistance. Because it's emptying the oceans. Because it causes suffering to billions of creatures with complex brains.
How do you think the general population reacts when you make these arguments?
Hypothesis 1: They understand the rationality of your arguments and engage constructively. Unlikely.
Hypothesis 2: They lose it and get furious. Because they feel attacked in the very foundations of who they are. They have a little furious voice whispering: "This person is challenging your social group! You can't allow it!"
Unable to kill the speaker as they might have done 5,000 years ago, they rationalize an unpleasant feeling by generating pseudo-rational excuses to invalidate the "opponent" and defuse cognitive dissonance.
The classic excuses
- "But B12! It's not natural to supplement!" — False.
- "Where do you get your protein?" — False premise.
- "Not eating meat is effeminate" — No comment.
- "Gluten is bad for you" — False, if you're not celiac.
- "We evolved as hunters" — Sure, good luck feasting on meat regularly before animal husbandry.
- "But avocados pollute!" — Right, a steak definitely doesn't pollute ten times more.
Obviously this response doesn't refer to everyone, only to the people described in the question. There are plenty of highly intelligent people who don't fall for these biases.
