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.