I like zombie films because I like to see morons get eaten.
I can second that. While I am not so big on the deaths of the inoffensive, I particularly enjoy watching zombies munch down the truly deserving. But I suppose if zombies only ate a$$hats, it would stretch credibility.
Plus, like a lot of post-apocalyptic themes, its a take on how we, as humans, would deal with it. Some would rise to their best, some just try to get by, and some would descend to almost zombie like behavior themselves, preying on whoever they could for their own benefit. And, I am sure, plenty would "opt out", as Dr. Jenner said in The Walking Dead.
