This argument is moot.

As long as humanity will want to kill eachother, everything will be used as weapons. Computers are used as weapons (hell would computerized bombs and missiles be possible otherwise?) boats are used to kill people. Airplanes used to kill people. So now robots, why not its the next step. Knowing the US government they will manufature them without any bit of encryption and with a radioshack remote control someone can hijack one of these :P