Or like saying that "The right to own a car does not mean that you have the right to drive it".
Or even "The right to own a car does not mean that you have the right to drive through red lights".
The fact that you can own something does not mean that you have the right to use it indiscriminately. In this case (if we consider them "digital arms") I don't see how using it for retribution (rather then self defense) would be considered ok.
And even if you don't have a drivers license it can be perfectly legal to drive your car on your own property (hack your own computers) but not to drive on public roads / private property where the owner has not consented to you driving (hacking someone elses computer without their ok), but if they are ok with it it's perfectly legal (like for instance pentesting). Context matters.
Or even "The right to own a car does not mean that you have the right to drive through red lights".
The fact that you can own something does not mean that you have the right to use it indiscriminately. In this case (if we consider them "digital arms") I don't see how using it for retribution (rather then self defense) would be considered ok.