Not everyone's gonna spend years of training to try and defend against a gun to the head. Chances are, if they sneeze, jolt etc. They will be shot. Not many people are faster than bullets. The aged and the very young can't do anything at all. Yes, they shouldn't be so harsh with self-defense, but it wont help against gun point in general.
If an assailant gets that close to you then you've already failed. Nobody is faster than a bullet.
The death penalty isn't going to protect you. It has not proven to be a deterrent anywhere. Further it will take decades to investigate, arrest and prosecute every murderer. There seems to be this delusion that somehow the death penalty, assuming it were an actual deterrent, is going to bring down crime in the foreseeable future. First you have to actually be able to get to the point of successfully prosecuting criminals. How is the death penalty going to make any difference to dangerous criminals being out on bail?
My wife and I could be considered amongst the aged. She never goes anywhere without her handgun, a knife and pepper spray. Now admittedly she has experience in hand to hand and weapon combat from her youth, but what really keeps her from harm is vigilance - both of us are too slow and old to handle an attacker who already has a gun pointing at us so we pay attention to our surroundings at all times.