Well, I’m actually not a consequentialist nor a utilitarian, but I think those arguments are actually stronger than the moral ones in many cases. I just happen to prefer cooperation over conflict because I do. I believe in the golden rule (ethic of reciprocity) because I do. I didn’t reason to that belief, though I did use reason to cut away at all my beliefs and find their foundation, and my worldview sort of restructured on its own. However, not everybody will necessarily recognize the immorality of aggression, and that is where the power of the consequentialist and utilitarian arguments enters.
Crusoe, Morality, and Axiomatic Libertarianism by Nielsio explains briefly what I’m talking about. People can prefer libertarian property rights because it protects their own property rights. If you want your house to not be invaded, then you support the rights of others to have their houses not invaded. That sort of thing.
So when someone makes the argument for aggression, this is a threat to everyone’s property rights. It’s one thing to support the invasion of someone else’s property if they started it, but it’s another thing to support invasion for just any old reason. Perhaps you’ve heard this quote before:
That’s the strength of a consequentialist libertarian property rights argument. If you aren’t consisent, then it could be you who gets aggressed against by the state.