If our intergalactic superiors landed here, but had no interest in eating us or our fellow animals, the first thing they could do is rob our stores, homes, farms, and warehouses of all our fruits, vegetables, beans, grains, and vegan convenience products. Without violating any vegan principles there would be no limit to the amount of food vegan aliens could steal from us — vegan ethics allows for humans using all the plant matter they want in the world, no matter how many animals starve as a consequence. Aliens could cause the worst famine humanity has ever seen, but it would be entirely compatible with vegan ethics. That’s because it would all fall under the rubric of ‘good intent’. They wouldn’t be killing us deliberately to eat us, but rather because they wanted our food and had the power to take it — our starvation would be a foreseeable, yet accidental, side effect. We might try to fight the vegan invaders over this mass plunder, but then they could kill us outright for threatening their lives. That’s because humans killing animals in self-defence is also no crime in veganism, even if we’ve wandered onto the animals’ own territory.
Since veganism doesn’t stop us from wrecking animal habitats to make space for ourselves, vegan aliens could knock down all our buildings to construct new ones that better fit their pan-galactic design aesthetic. They could evict us from our homes, businesses and veganic farms without compensation, and then, to keep us from returning, they could set up fences, noise barriers and other humane deterrents. To them, we would be hungry pests who threaten their vegan food supply, so they might even be justified in trapping us or killing us with poisons if we got too close. Humans would now largely be without food and shelter, but the vegan aliens wouldn’t need to lose sleep over it, since none of this contradicts any vegan tenets.
His point seems pretty clear to me — simply by existing as such a hyper-fertile species with a boundless appetite for space and resources, humans directly cause an incalculable amount of animal suffering whether we ever kill them for food and clothing or not. But I'm afraid you can't even take refuge in the consolations of misanthropy here. Schopenhauer, ferzample, a misanthrope par excellence, not only anticipated Tennyson's famous line about nature being red in tooth and claw, he turned it into a whole series of graphic novels, elaborating in detail just how much pain and suffering would exist in the world even if humans were removed from it. Agonizing violence and injustice permeate the animal kingdom, and humans, despite their best efforts to believe otherwise, are very much animals, a product of the "natural" world.
Commenters, though, seem to largely take issue with what they perceive as his implication that vegans aren't also committed to environmental and social issues beyond the ethics of using meat and leather. I suspect that the misunderstanding, if not exactly deliberate, is entirely predictable, almost preordained. People understandably don't like to be reminded that the values and efforts in which they take so much pride are largely vanity, and nothing is more vain than the belief that human effort and ingenuity will manage to unravel life's tapestry and reweave it minus the threads of suffering that constitute so much of it. I know from my own experience that many vegans are indeed interested in other social justice issues. I question the point, not the depth, of their commitment They're not myopic because they focus on too few areas of activism, they're myopic because they claim to believe that a world in which domination, exploitation, violence, injustice and suffering no longer exist is actually achievable.
Need it be said? Ahh, I'll do it regardless. No, the ultimate futility of efforts to eliminate suffering does not imply that suffering should be ignored or even encouraged. As with nihilism, attempting to draw such a conclusion is a last-gasp attempt to reassert some sort of universal law that can be blindly, faithfully obeyed. The point, rather, is to question what it would mean to make our peace with the presence of suffering as a necessary, ineradicable part of life.