Kizmelelf

TL;DR: From an ideological standpoint, fish are a better food than plants

It is important to remember, that from a vegan ideology, the only food that should be eaten is fish, as they are the only organisms that can't feel pain. It has been proven that plants do feel pain when eaten, and mushrooms have neural networks similar to our own in the mycelium, which rules out both of those categories. Then there is meat from animals, which is ruled out for obvious reasons. Leaving fish as the essential vegan food.