Grass-eater. I've not encountered it before, but it seems to be a useful turn of phrase.
An explanation via Blunt Object:
If you’re familiar with George Orwell’s novella Animal Farm, you can think of grass-eaters as the bipedal equivalents of the sheep. The term is intended to remind one of a herbivorous herd mentality, rather than simply munching green things. Grass-eaters are known for their passive-aggressive approach to life, society, and morality...
Grass-eaters are deathly afraid of anything resembling personal responsibility. They are prohibited from assigning blame to any human being — such an act, after all, would imply that they themselves might someday be blamed for some transgression! Therefore, grass-eaters blame just about anything that isn’t animate for society’s ills — weapons, rap music, video games, black trenchcoats, money, red meat, or the hormone testosterone. They’ll put the blame on ephemeral concepts, too — generally liberalism or conservatism, but masculinity, feminism, globalization, religious fundamentalism, and secular humanism are also popular favourites. Under no circumstances may an actual human being be held accountable for his or her actions by a grass-eater.
That said, grass-eaters fear and despise people who accept — worse, seize — responsibility for their actions, future, and well-being.