I'm not well up on the precise theory, but I'm pretty sure that the notion of artificially suppressing the natural behaviour of entire species, overriding their natural breeding rate and imposing an unnatural diet on them, especially genetically engineering them to be something other than what they naturally evolved to be, for perhaps no other reason than so we no longer have to be aware that they exist and harm each other, is every bit as anathema to the basic concept of veganism as simply eating them or using their byproducts would be.
This total contradiction of what should be this guy's core principles is, I suppose, inevitable given that those principles are completely out of whack with reality anyway and must give rise to huge cognitive dissonance, much like the average religion might. The basic, ill-thought-out view of extreme veganism and/or animal-rights seems to be that a world where humans do not impose their will on any other creature would be some kind of idyllic utopia without pain or suffering for any creature (and desirable by definition), which of course completely ignores the fact that plenty of other creatures evolved, entirely naturally and without human meddling, specifically to exploit and even kill and consume many others.
Some vegans, or at least their closely-related ilk in the animal rights movement, also seem to have the notion that the same human rights (self-determination, ability to deploy force often to the point of lethality, etc), which even we ourselves, in the more properly functioning of our societies, only fully grant to other fully developed humans capable of comprehending and acting within the social responsibilities that are inextricably bound up with those rights (trivial example: even societies where adults are allowed them generally don't give an eight year old an automatic firearm, even though that restricts his ability to self-defend, considered a basic right by many of those adults), should be granted to all other creatures, regardless of the fact that effectively all of them are patently even less capable of handling such power with any kind of conscious responsibility.
Back when humans themselves were little more self- or world-aware than any other animal and largely worked on dumb, hardwired instinct, this situation would have been acceptable (were there any external, intelligent observer to find it so), and evolutionary mechanisms would have handled everything for us, giving us fair and equal treatment to any other living thing. Now, however, it seems to my mind that there is simply no way to reconcile the continued existence and operation of humanity as a sentient, consciously self-determining species with our total renunciation of any deliberate diversion of the rest of our world from what its natural course would otherwise be, which is ultimately what the core of at least certain strains of animal rights and vegan movements requires. Merely deliberately erecting fences or buildings, not even about animals to pen them in but about ourselves to prevent predators and parasites from accessing our own small personal space, is an act that imposes our conscious will on all other creatures in the immediate area (the argument could be made that, were we to do everything we do now but entirely instinctively and without awareness of it, like an animal would, it would be an entirely different moral situation). As for the construction of entire cities, not to mention vast tracts of rail track and asphalt road surface, the impact on any other living thing in the area is really quite huge - to be absolutely true to the ideal of having no conscious influence on other creatures, we would not only need to renounce every work of conscious human artifice, right down to the last mudbrick, we would then need to consciously renounce consciousness, and thus the ability to devise and impose restrictions upon nature, altogether. This would be an ultimate irony, as consciousness itself, although giving rise to our ability and even our desire to act against and control nature, is the ultimate product of the most natural of all processes, evolution. (perhaps there is something in the view that the ultimate purpose of any consistent, self-improving system, like evolution or human society, is actually to make itself redundant and bring about its own successor)
Though many may seem harmless, well-meaning kooks with an admirably high level of compassion (at least towards animals; other humans sometimes don't seem to be included), the vegan/animal rights ethic (not, I should stress, the vegetarian one - that merely suggests finite, sensible limits on our imposition on nature based upon compassion and the bounds of necessity, whereas veganism ultimately seems to demand a limit of zero) is actually a deeply unsettling one, and I think could do spectacular damage to human society and the entire ecosphere if given real power and pursued by fundamentalists like this guy.
Perhaps I've taken my argument too far. Though it certainly applies to fundamentalist animal-rights nuts like the ALF, it may not necessarily apply to all versions of veganism. Veganism, it seems, only usually asserts that animals are not ours to use for our own benefit - the question remains, however, whether it holds that animals are not ours to control, even passively, even for their own good, let alone ours, an extremely similar but, nevertheless, distinct restriction that would, perhaps, validate everything I have argued above.
