Well, are manned supersonic planes a threat to all of us?
In a way yes, as they can be used to carry a nuclear warhead. In a way, they aren't. In a way they are awesome, and I want more of them, esp. in civilian use (like a successor to the Concorde program).
I am a huge fan of the civilian use of UAVs*, but do accept the fact that military use has been, and will continue to be an important driving force behind technology.
It's not the technology that is a threat, but politicians (and grassroots fanatics) who make wars. While the H-bomb is usually seen as a threat, I do think the threat of mutual destruction just might have stopped some unresponsible and downright insane politicians from going to war once again.
And you can kill millions with nothing but Kalashnikovs just fine. You don't need tech for that.
* - Those interested, check this out:
https://www.youtube.com/user/nastycop420