By the way, If you would say WWZ was kinda unrealistic, well zombies are kinda unrealistic. Its fiction. Zombies, of the non-voodoo variety are pretty much defined by British and American Pop-culture. 28 Days(Weeks) Later, Dawn of the Dead, Return of the Living Dead...Night, Day, Land. You name it. Comics? Sure. Books? Even better. Its suppose to be fun, but its been named possible because of the way it happens.
One zombie, the spread, the blood bath, the slow burn, the failed fight, destruction.
Survival. Thats what draws us to the idea of zombies. Undead, which do not breath. Which do not sleep. Which do not 'need' to eat, but feel a neverending drive for flesh. Those, which can not feel emotion other then a lust for blood.
Or anger, uncontainable rage that is triggered by chemicals from some freak lab experiment. If you don't see my point, its that zombies as what were talking about, have all those attributes and more. If you say your talking of zombies that can breath, then your talking of zombies that arn't zombies. That arn't UNDEAD. The very idea of zombies is simply them being mindless eatting machines, that spread terror, and the infection itself, until were either all dead, or they burn themselves out. Whether or not one gets stuck in the snow for later terror is not the point.
A zombie, is defined by what the majority, hence the pop-culture, define it as. I think it's really a way of saying that if Humanity grows to large, it'll eat itself to near death, then burn itself out. Engage restart.