I really couldn't be bothered to read all of it, I just needed to point out two things.
Yes, the crime rate did go down in Russia, under a regime based on terror that killed almost every criminal, and person who disagreed with the system. My point being, that yes, capital punishment CAN reduce crime. So can implanting small bombs in everyone at birth and give the codes to the government so they can blow everyone up when they want to. And of course, keeping everyone locked in a room with no outside contact and only a work file delivered everyday would keep crime even lower.
Basing a system on terror isn't a viable option these days, sure it works, so does dictatorship, despotism and killing everyone who disagrees with you.
Then you go on saying that almost all activities we partake in kills innocents. What the hell kind of a logic is that? Shouldn't the answer to that be to try and stop that from happening, rather than kill more people? Drunk driving probably kills some criminals every year, let's keep that too?
Then you go on talking about the costs. Why not have the criminals pay for it? Hand them a bill when they get out, or better yet, give a job in the prison, producing goods or something, so that they can keep it up.
You aso go complaining that it's inhuman to keep people in dark, scary, claustrophobic rooms, and that's nicer to kill them. Why don't you ask them what they think about it? You're not the one getting thrown in there, after all.
After that, I'd like to ask, what's the point? So you have a murderer. What good comes from you putting a bullet through his/her head? He/she's dead, yeah. He/she won't kill anyone else, no, sure. There are other ways to prevent that. There are ways that he/she could still be useful to society. You don't solve a problem by killing a person. If that person had a reason for killing someone, another person will also find a reason for it. You don't remove the reason behind the crime by killing the perpetrator.