Sentimentally wrongheaded
The man is suffering from a failure of concrete perception. It's increasingly common nowadays, as people make judgments based on comforting abstractions while shielded from the pitiless impact of reality.
What's cruel is being hurt; death itself isn't bad at all, just as long as it's very quick and more or less painless. Being hit on the head by a one-ton bomb isn't very cruel at all, as you're unlikely to know anything about it. One moment you're going about your business, the next there is no you to be doing anything.
The worse the injury, the less susceptible to effective treatment, and the longer before it can heal or be alleviated, the more cruelty. Being stabbed seriously is quite cruel, especially if you can't get to a nice sterile well-equipped hospital with modern anaesthetics. Being shot in the guts is cruel; so is being hit by blast and/or fragments from that one-ton bomb if you are unfortunate enough not to be killed outright.
Worse, IMHO, are being burned by a flamethrower, covered with napalm or white phosphorus, killed by slow-acting poison gas, or being caught by radiation from a nuclear weapon. Not to mention surviving (injured or otherwise) while your parents, children, siblings, etc. are killed or maimed.
A small, low-flying robot drone is perhaps more likely to score a direct hit on its target, thereby killing him/them with a minimum of extra suffering. As the article points out, a manned bomber usually stays good and high to avoid the slightest risk to its precious crew, and - as manned bombers have for the past century - probably misses its targets by anywhere between 50 yards and a few miles.
If we want to reduce cruelty, we should consider giving up the habit of killing people we disapprove of (or trying to kill them and killing others instead). Our glorious leaders should ask themselves, as seriously as they can manage, "whom would Jesus bomb"?