No. He killed an innocent man in the most brutal and depraved fashion possible in that situation. That isn't "protecting [your] wife and kids." That's cold-blooded murder.
If you don't see any other way out and decide it becomes someone else or you, it could be a choice you make. In that moment things sound like they seemed to be one of 2 options in the character's mind, staying stuck in there and the zombies get them or throw them some bait to distract them.
Were there other options, probably, but in that character's mind he's doing what no one else will and doing it b/c he views staying there as signing their death warrants. By definition, if the zombies don't eat your kids through your actions, you protected them from the zombies. His character will have repercussions from the actions and that is as it should be.
Admittedly, the OP admits to no familiarity w/TWD specifically when it came to zombie fests. To go back to the super hero game, it would be like the GM saying we're playing 4 color and rather than see what the difference was between that and more modern comics, the player who has only read The Dark Knight Returns and Watchmen makes an anti-hero.
I'm not disagreeing that some of his character action ideas, largely from his 2nd post in the thread, are against the specific sub-genre being discussed, but I think in a life and death situation someone might make the decision to throw someone to the wolves and the results of that would make for interesting gaming IMO.
Playing someone that no one trusts who maybe becomes more trustworthy over time is certainly within genre. Merl's brother never went as far as the OP's character did, but a lot of his opinions that made him more of an outsider early on have certainly softened over the course of the show.
Is that something that would happen in a film (or in real life, for that matter)? Absolutely. But what happens if everyone acts the same way. How long before it is your turn to be sacrificed for zombie bait? If the rest of the group had been smart, they would have cold-cocked the OP right after he knocked out the other guy.
Imagine if the group had all been federal prisoners in for life for murder. This would probably come up a lot more often. I've played in games where anti-player action wasn't off limits. Everyone knew what was going on and didn't get their feelings hurt. He didn't do it to anyone around the table tho. Was it murder, sure, but the other player's reactions to that will inform a lot of what happens in the rest of the game.
How do you know he saved the party? The party could have had another way out (I listed several different possible options way back in this thread) very easily.
I'm working under the assumption that his character figures he saved everyone, which seems like a reasonable line of thought to me given the actions that construction worker has already taken.
He was just tired of talking about it and didn't want to wait for a group decision. There was no indication in the OP that there weren't any other options for the group - he took it upon himself to take charge and pound the guy into unconsciousness & toss him to the zombies.
When he didn't like it was when they went inside the diner against his wishes, and once inside the place he didn't want to be, he decided he wanted to be the leader of the group. When somebody wanted to come to a group decision instead of submitting to his absolute authority, he decided to stomp the guy and then toss him to the zombies.
There has been a vote of no confidence. He ended up being judge, jury and executioner, but he didn't think someone's leadership was working well and didn't think there was time for a discussion. He could have been right about that, we don't know. *shrug* I'm actually really curious to hear about what happens at the next session.
Also, the game did end after that, but we don't know if that was an early end to the game, which many people seem to be assuming or if they just got to their normal end time. I know if we're close to the normal time and we just finish a big scene we'll just call it there. I didn't read it as his actions were session-ending and was honestly kind of surprised so many people did.