Kirk caught up to the big evil villain, shoots him.... ONCE... and then decides to TALK to him?
Kirk: "Yeah so I'm gonna risk the millions of lives here, on the off chance I can talk some SENSE into this maniac... yeah, that's what I'm gonna do!"
Wouldn't any SANE person shoot that guy 7 times and then again a few times AFTER he was dead and/or vaporized? Just to be sure he didn't get those last few yards and released the horrible virus?
Kirk very nearly got everyone killed, good thing noone on the base noticed Kirk HAD him but then decided to start talking. :D
That's a common theme with Kirk, he tries to save/redeem the bad guy, even if it's risky to do so, because it's the right thing to do. He's extraordinarily moral. It's heroic but as you say, somewhat foolhardy.
In this case he didn't have much to lose by trying. If Krall/Edison made a move for releasing the nanovirus Kirk still could have responded exactly the same as if he didn't attempt to win Edison back over through talk. But there are other movies/episodes of Star Trek when he really risks his own life to try and save the villain (Star Trek III The Search For Spock leaps to mind), even though it is absolutely unwarranted to do so. It's just the kind of character he is, he's a man of conscience and moral fibre.
"In this case he didn't have much to lose by trying."
Except the millions of lives almost perishing because Edison disarmed him, you mean? :)
I think you and I have very different definitions of both "the right thing to do" and "not much to lose". :)
The right thing to do, is help out the innocent for instance.
I don't think it's the right thing to do, to talk sense into a guy who personally has killed a handful of my own crew members, and is responsible for countless others, and who is fanatically determined to kill millions more.
I wouldn't give that guy a second chance, OR the chance to disarm me and succeed with his plan... but maybe I'm just harsh.
Edison was a war time hero who felt he had been abandoned by humanity and then lost his way and became angry and bitter, as a fellow Starfleet captain Kirk wanted to give the guy a chance, he felt he had a moral obligation to help a guy who had helped preserve the Federation and to give him one last chance to change his mind.
Edison was a tortured soul and became a villain because he felt that the Federation had turned their back on him after he gave the best years of his life to fight for and protect them, you don't think that maybe he deserved a shot at redemption? Kirk had the drop on him and was confident that he was in control of the situation, and as I said he's a man of conscience. To Kirk it's not a question of "what is the safest option?" it's "what is the right, morally obligated thing to do?", and he chose to talk to Edison rather than shoot an unarmed, tortured man.
No, personally I don't think mass murderers should be given second chances, no matter how much good they might have done BEFORE they decended into madness.
Picture this: You see a terrorist with a huge nuclear bomb in the middle of a big city, about to press a button to detonate, YOU are the only one who has spotted him: Do you think you are "morally obligated" to try and talk some sense into that man, even if you know you have a chance to shoot him and save millions of lives by killing him before he presses that button? Is talking to him the "right thing to do"? Perhaps he was once a good man, perhaps a nice paramedic, a fire fighter, or maybe a nice HERO who is now just a "tortured soul", so he too deserves a second chance, does he not? in spite of that nuclear bomb he is as "unarmed" as Edision was with his bioweapon.
My answer would be the same: No, if you have a chance to stop someone from killing millions, THAT is the right thing to do, THAT is your obligation to those millions of innocents who depend on YOU to save them.
Oh if it were me I would have shot the son-of-a-bitch.
I'm talking about Captain Kirk here though, paragon of morality and optimism and virtue. Hero of the Federation. He'd give Edison a chance to turn away from mass murder even though he had become a super villain who had fed off of the lives of countless aliens to prolong his own life over the centuries. Kirk would forego all of that at the chance of not having to kill him and give the fellow (although ancient) Starfleet captain a shot at redemption. That higher standard of morality is important to Kirk.
Not to me though, I'd have shot him, and I would have shot to kill. Yes Edison is a tragic person and what happened to him isn't fair, and perhaps he deserves a shot at redemption for what has befallen him and as a Starfleet captain he still has the twinkle of righteousness in him that just needs to be stoked to reemerge itself, but like you I wouldn't take that chance. I haven't sworn any oath to Starfleet nor to any higher morality, and I'm not heroic. I wouldn't take the risk just because "it's the right thing to do". I'd kill him and would sleep very well the next night afterwards too.
And they didn't even use the excuse that Kirk had his phasers on stun but Edison's enhanced body mostly shook it off; Kirk would have tried firing more times if that was the case. Stun would have saved the day without upright killing Edison.
Of course, Kirk showed no qualms about killing Nero was also guilty of countless murders. Was Edison more sympathetic because Starfleet rewarded him and then couldn't find him after a wormhole versus a man who went crazy after his family and entire planet were obliterated?