If you're plant-based for the planet, and science invents a magical carbon-sequestration machine that mitigates climate change, and a new hybrid cow that gives supermilk and only requires 3 sq ft of grazing land, you'd stop being plant-based.

That's why we don't call you vegan.

If you're plant-based for health, and we discover some extraordinary fish, or like a gopher or something that's 10x healthier than any food known to man, and lowers cholesterol, reduces wrinkles, and cures ED, you'd stop being plant-based.

That's why we don't call you vegan.

If you're plant-based as a diet, you have no reason to avoid leather, silk, fur, ivory, the zoo/aquarium/circus, animal races, horse riding, rodeos, dogfighting, bullfighting, etc.

And nearly all diets allow or encourage occassional cheating.

That's why we don't call you vegan.

Health and the environment are fantastic reasons not to kill animals, but they're not even remotely the main reasons.

Vegans are vegan for the animals.

Anything else is secondary.