[comex]

My view is that it's largely about realism. Even in today's first-person shooters with fancy HD graphics, you're usually aiming at a person who pops in and out of a single cover location, conveniently waiting for you to shoot him. Even if you've killed all his buddies, he won't run away or do anything different, but just keep yelling generic insults at you. If you shoot him, but not enough times to kill him, he will start shooting you again after a few seconds, seemingly no worse off for the injury (just like your own character). If you kill him, he will make a generic yell and fall over, but never die any more gruesome way. His corpse may have some blood around it but won't look remotely realistic. Originally this was basically mandated by technical requirements, but today it would certainly be possible to go further; I suspect most games don't do so precisely because players would feel weird being more realistic killers.

That's for FPS. In this game, even though the opponent has a face on their profile, the shooting consists of hitting a button and seeing a health bar go down. It's so abstracted from any reality that it's not even close to a problem.