Good point in a broader sense.
How is an this different to a dog? Dog also lacks "compassion to make complex decisions" - when it's trained to attack the guys wearing red bandanas, it will attack guys wearing red bandanas. We've been training dogs to hurt or kill humans for millenia.
The only difference is that dog is "alive" and AI drone isn't. But that's just a matter of definition.
Generally, dogs have more compassion than most humans. Just saying.
Agreed: A dog brought up on pain training, becomes basically a psycho and has no real control of it actions.
Funny thing: WW2 the Russians trained dogs to go under tanks, using reward etc.. However. On the day the said dogs had explosives strapped to their bodies (the intention of the training) the dogs only crawled under the tank they knew: The Russian ones.
As to the use of using animals as weapons, it is reprehensible and the ideal, that it saves a human being at risk, is just wrong. Most trained animals, are loyal to a fault and to exploit that and endanger the animal, is just cowardly.
Things like sniffer dogs, with not be replaced any time soon, due to their abilities and flexibilities. Making a robot manage to do the same, is well beyond current engineering. Sniffer dogs can and will be improved and therefore stay a step ahead of their robot replacements. A handler can now talk a trained dog through an environment, from a remote place. The hander can see and hear, what the dog can, in real time.
It's ... not a joke. 
