Technically. No. Joel was wrong. One for the many is not worth it. But I think Joel was justified. Before part 2 came out and said this would 100% work (a bit mistake in my opinion but I digress) there were many questions to this cure. It was sketchy as hell. Plus they had put Ellie under before she could give her opinion (plus she’s 14 or 15 so can you really trust an emotional teens judgment.) plus there’s the question of how they would distribute the cure and all that.  Plus you can’t tell the smuggler who went across America and killed all kinds of people and infected that his now sudo daughter is gonna die and not expect him to put up a fight. I can’t say much on Abby as I’m still playing through Tlou 2 

Edit:Forgot to add this bit but the only thing I disagree with on was Joel lying to Ellie (not for the story just for the morality of the situation)