However, regarding what the writers put into the show, the group, before Rick joined them, was putting up with a whacked out bigot on drugs who seemingly regularly pointed a loaded weapon and professed that he though some of the group members were less than human.
100% correct.
That would seem to pose an imminent life-or-death danger to some members of the group.
Correct to a point. He's definitely a threat, but not as imminent as the walkers.
Yet, in that setting and for those characters, they put up with Merle, perhaps because he was not a walker and they figured having an extra gun against the walkers was worth the risk.
Yep. And were I in that situation, that's the calculus I'd make. Especially since I'm no mind reader and have no idea how many others in the group sympathize with his position.
Plus, it might be that they were not prepared to take a human life themselves and telling someone to leave who was like that was risking that he would kill them himself, if only to take all of their stuff.
Yes, which is why, if he so egregiously violates the unwritten social contract of the group by actually being violent towards the group, he either gets killed outright or you have a blanket party to disarm him before exiling him.
Seems to me that in the OP's game the other players could just as easily play up the fact that they are not murderers and don't feel they have the right to take the OP's character life, even if some of them are doing it out of fear of retaliation or fear of becoming the very thing they condemn, or any number of other reasons that might prevent them from having to boot the OP's character from the group.
Sure.
But I was speaking for myself in that situation. Someone violent enough to kill over dissent- especially dissent in the form of asking for a vote in a group with no acknowledged leader- is not someone I'm going to trust with my back. We're parting ways, one way or another. And given the totality of circumstances, I would do ny best to make sure I was the one who got to stay with the group.
If the OP is now aware of the show's dynamics and is getting more on board with that mentality, there's no need to retrofit anything. The incident at the Cool Room just becomes an important part of their early story and a regretable freak out moment for the OP's character for which he now has to atone.
Sure. But again, unless I saw actual evidence of in-character contrition, he's on my hit list because my distrust of him would be at least as great as my fear of walkers.
People keep bringing up PvP but it is my understanding that PvP isn't part of what has happened here. Did I miss something?
No, technically, PvP's not what happened between the PC & NPC, but it would be one possible consequence of that killing.
Frex, shocked and scared by the diner incident, my PC would try to kill the murderous PC, leading to PvP. The questions would be how, when and how obvious would I be, not whether...and all would be answered by in-campaign dynamics.
I say that having done so before, a couple of decades ago, in a scenario only slightly less serious than this one.
when an NPC tries to take a leadership role it is problematic in an RPG.
Asking for a group vote on a path of action isn't taking on a leadership role, IMHO.
And even if it were, it doesn't rise to the level of a capital offense.