These machines are becoming more and more advanced, and lethal, every single day. Soon, wartime operations will be able to be carried out completely autonomously.
During wartime, more than enough innocent civilians die at the hands of humans, by making it viable to kill without even sending in other humans, death will ensue and rise perpetually. What was once considered a war-crime will become nothing more than collateral damage.
By allowing the continued use of mechanical warfare, we are setting a dangerous precedent for the future of the human race, and the value of innocent lives. This should be halted immediately due to the high volatility of human rights violations and costs of collateral damage.
In a world meant to be considered civilized, there is nothing civil about using automated machines to kill men.