It surprises me because they apparently don't know the source material. The Zerg have never really been portrayed as "animals" but the result of a malevolent hivemind of sorts, with the zerglings and battle creatures being the extensions of the overmind, in a way sort of like how we have hands and feet.
In RL I have what is very much a "people first" mentality, BUT that doesn't mean I'm entirely callous in dealing with the enviroment or animals, I just don't think a bunch of yellow spotted frogs have more rights than humans do and I don't support dealing with social problems by creating more housing and such being derailed for their sake. That said I feel as time goes on, more of these clean energy sources come online, and we gain the technology to build our cities upwards, colonize other planets, and similar things, a lot of these problems will correct themselves along the way. Yes species might go extinct, but again... people first.
I tend to be more concerned about species that get along with us and are useful. I understand the idea of an interconnected ecosystem, but at the same time I have a hard time preserving species that would kill me without breaking a sweat. "Pity the poor, tiny, nearly invisible spider with it's acidic poison that will make your heart melt after a minute of horrible agony, and will aggressively bite anything that comes too close to it's nest..." and things like that, snakes, giant lampreys, angler fish (I mean seriously people, those things exist to give your nightmares something to be afraid of), and similar. I tend to really like big cats and other large predators as kind of an exception, but I mean even so, while I don't want them to go extinct, I don't want to preserve them to the point where I can get mauled by a Mountain Lion or Bear just wandering around. With no offense, all comments about misunderstood species, you'll notice a lot of these creatures tend to maul people horribly if they accidently get inside their enclosure ad zoos where they are used to people (and even more domesticated ones have accidents... Siegfried and Roy's white tiger mauling, comes to mind, as does a certain monkey face-devouring incident).
I guess I'm rambling, but to me I've always felt the biggest cure for the people in groups like PETA who tend to mostly be isolated hippies with white guilt complexes from waht I've seen, would be for more of them to get mauled or killed by some of these animals. I mean seriously when your a jogger that gets attacked by a Mountain Lion or whatever, it becomes seriously obvious why we've hunted them like we did. I think what we sort of need is a special PETA Bus Trip to Yellowstone, where instead of following policies the PETA members will be encouraged to get out and frolic with and feed all those cuddly bears... I mean they are used to tourists, nothing bad could possibly happen doing that....