They didn't "get involved', they were born with enemies by the sheer fact that they were born Jewish.
Yeah, and a couple of Hatfields didn't really wanna fight the McCoy's but then a McCoy shot their big brother, and well, they HAVE to defend themselves against these sorts of actions.
It's a fucking vicious circle with the only constant being a bullet or a bomb at the focal center. Any notion of 'blame' falls squarely on the guy pulling the trigger or pushing the button - not his brother, not his cousin, not even his dead great-great-great-grandfather. I am fully aware that you disagree, but that doesn't change my beliefs one bit. I'm sorry that's the way it is, I really am.
