Humanity has certainly gotten better at perfecting projectiles and the methods used to transport such weapons. Undoubtedly there were those who thought the advent of the gun on the battlefield made war less personal than the weapons before it such as the bow and arrow which required a closer proximately to your enemy. And let's not forget our old brothers, the Neanderthals. They had very personal battles face to face with the use of clubs rather than any projectile weapons, does that face to face battle until death really make them less callous than a snipper or drone operator?
i know the point you're making. this is the rational consequence of human technological development. our lives are improved by the same technology in a million different ways. and yet this fruit of rationality can be ugly because it makes the brutal more efficient and dehumanizes. consider the bureaucratic efficiency with which jews/poles/other germans were killed in WWII. with neat little memos from middle managers sending train loads of people to concentration camps.. killed by a faceless bureaucracy. is modern bureaucracy the most efficient way of organizing people. yes. does that change the fact that this efficient and faceless murder is monstrous? this has only been extended now to the hand that pulls the trigger, so they too can be divorced and detached from what they're doing. it is also more than the increased range of weapons.. it is that killing someone has lost its meaning and consequence, with this immersion in media, with this similitude of games.
the act of killing is the act of killing. how it is done says a lot about the values you have. the western civilization is headed towards an almost unconscious, impersonal, semi-automatic, unreflective ... callously indifferent form of murder, where the consequences of what is done never registers... where there almost is no agent at all, where the notion of individual or collective conscience is anachronistic.