A lot of contemporary weaponry is already fairly autonomous. For example, it would be trivial to program a modern anti-air missile system to shoot at all detected targets (matching specified criteria) without any human input whatsoever -- no AI needed. And, of course the difference between offensive fire and defensive fire isn't all that clear-cut. Is a counter-aritllery barrage offensive or defensive? What about area-denial weapons?

I have a feeling it's a typical feel-good petition ("I Did My Part To Stop Killer Robots -- What About You?") with little relevance to military-political realities.