"Animals that eat leaves off of trees and urinate on shrubs are environmentally destructive as well..."
A few years back I went to Kruger Natl Park in South Africa. Just after we entered the park, we drove by four or five fairly large trees that appeared to have been uprooted by a tornado. I asked my guide whether they had tornados in South Africa, to which he replied, "No, but we do have elephants."
Indeed, later in my trip, I got to see a bull elephant in the process of knocking over a 8" diameter tree. It seems a lot of work to get a few leaves at the top; I guess they're a delicacy if you're an elephant. Anyway, the elephants' environmental practices are clearly unsustainable because they have to be culled to prevent deforestation. Perhaps the Voluntary Extinction folks would promote the extermination of elephants also?