Indeed they do, if they wish to rationally claim it as a moral imnperative for themselves.
Those who are willing to initiate force against otherwise peaceful men, rationally preclude any claim they might make to such a moral imperative.
Have many done so anyway?
Sure.
But their actions cannot be rationally defended or sustained consistent with the notion of morality.
Hence, they act immorally.
No they don't. They can rationalize anything they wish. It's only YOUR morality that compels them to follow your rule. They can simply live by "Let the buyer beware".