stj has a point (one that was expanded on in this article), it's a very flawed metaphor. In the real world, people's rationalization of their objection to homosexuality is due to what they see as "moral" reasons which I think we can all agree are BS. But in the True Blood world people object to vampires because they think vampires are murderers. And, they're right, in the True Blood world vampires are murderers.
I'm pretty sure that most anti-vampire groups don't give a shit that vampires are murderers and many of them are probably pro-murder.
They seems to be mostly motivated by the fact that vampires and icky and different and the violence really doesn't matter to them one way or another.