MAJOR SPOILERS!!!
I think this game is great, I love the character of Joel one of the best characters ever made but I believe his death is justified as he did rid the world of a potential cure making IN MY OPINION Joel the villian of The Last Of Us story as is explained about all the bad stuff he did during the 20 year skip in the first game that he even tells Ellie the stories of the things he did to survive and killing all the fire flies and the opportunity for a cure and telling Ellie the lie.
I feel like Ellie going on a rampage is more to do with the fact that in her mind Joel had died thinking she hated him and she didn't have the opportunity to forgive him fully for what he did so her journey is from grief and revenge on that thought.
Abby killing Joel can be justified as IN MY OPINION she's not the villian in this story she only did what she thought was right as Joel did kill her dad and all the fire flies which she probably thought as family to her and stopped the world from having a cure and throughout the game she's very caring and not at all a bad person.
If everyone in the world knew what Joel did I'd say everyone would hate and ostracize him for what he did except obviously Tommy as he knows exactly what Joel has went through with his daughter and some of those 20 years they were together he understands and is his brother and the opening minutes of the game he did tell Tommy.
Anyway it's an amazing game and a great sequel. ALL IN MY OPINION