Huh, I've not heard any vegan talk about that. In fact mushrooms are a staple in many of the vegan foods I'm aware of

By definition are vegans those that don't eat or use animals or animal byproducts.

Fungi aren't animals. If this group doesn't consume fungi then they should call themselves something else entirely to avoid further confusion. Maybe they should go strictly by herbivores.

Eh, the parts people eat are not the mushroom itself. The mycelium underground doesn't give a shit if you eat its reproductive organs. Hell, it probably likes it.

Not some. They are taxonomically more related to animals than plants. Just a fact.