And that's according to the people who murder people with them:
Four former US air force service members, with more than 20 years of experience between them operating military drones, have written an open letter to Barack Obama warning that the program of targeted killings by unmanned aircraft has become a major driving force for Isis and other terrorist groups.
The group of servicemen have issued an impassioned plea to the Obama administration, calling for a rethink of a military tactic that they say has “fueled the feelings of hatred that ignited terrorism and groups like Isis, while also serving as a fundamental recruitment tool similar to Guantánamo Bay”.
In particular, they argue, the killing of innocent civilians in drone airstrikes has acted as one of the most “devastating driving forces for terrorism and destabilization around the world”.
There's more, but its basicly what we've known all along: that you don't defeat terrorism with terror. You don't defeat murder with murder. Instead, that just gives you an ongoing problem where your efforts to solve it continue to feed the cycle and make it worse. And the only people who do well out of that are terrorists, militaries, and the parasitic industries who feed them.