It struck me too...watching the Others gather eagerly to watch Locke cut a helpless man's throat...however just that death might be.
But then I was thinking. No one ever, EVER, addressed the morality of killing a man. Ben, at the end, goaded Locke by recounting his father's crimes and mocking him, but until then no one had phrased the quandry in light of its ethical or moral implications, nor from the standpoint of justice.
It was ALWAYS addressed from a perspective of "Locke needs to do this, so Locke can move on." It's for Locke that this must be done. To free him from his past.
Now, that sort of thing can be a brainwashing technique. Where you pressure someone into doing something really awful, that they can't justify or rationalize to themselves UNLESS they totally accept the will of the group and their own subordinate role to it. But given the other events on the island, it struck me that the Others might actually be onto something here.
Ben lies easily and constantly, sure, but even the Devil can tell the truth for his own purposes.
When Ben spoke of Locke "bringing him here," in reference to his father, I started wondering...just who is this guy tied to a pole (and that stone ruin was -incredibly- out of place, don'tcha think? Old temple pillar? Huh?) for him to kill? Was it Locke's father? Or an -image- of Locke's father? A manifestation? A projection, somehow, of the 'father' that lives in Locke's head, holding him back, demanding to be dealt with.
I don't think he was a real guy. To me, that explains a lot about the -utter- lack of concern the Others showed towards him...not even addressing him or looking him in the eye. Only knocking him out so he can't say too much. Jack's dad was the same way. A lot of the other things on the island are too, I think. The 'magic box' doesn't just give you what you THINK you want...it gives you what you deep down subconsciously want. And what Locke wanted...almost as much as to walk again (which he got too) was to square things AT LAST with his dad.
How does he know about being in a car accident and so on? I have two ideas about that. One is that it could be just made up...details from his fantasies or speculation from his unconscious. The other is that, by that time, our con man had TWO authors...Locke AND Sawyer. He was unusual in that he was the focus of two men's vendettas, and it's possible that Sawyer knows something Locke (and we) don't. I also kind of wonder if Locke might have heard of a car accident involving his dad...
And yeah, it doesn't pass the Razor test.

It just has seemed to me that there's been SOME kind of psychoreactive element to the island from Season 1. It might also explain why the con man was so...forthcoming to Sawyer. *shrug*