[SPOILER AHEAD]
Most of the people hated it but I'm just gon be honest w ya. Abby is no doubt so hateble at first but imagine what she's been through its actually pretty understandable.
And yeah that's the whole point of the game, trying to make you feel something good about Abbey but let's be straight, Joel's final decision taking out the whole Firefly base back in Part 1 ain't the right thing to do as well, he know he's no hero, we all know that, discussion about the humanity and morality of the ending is all over the internet back then.
But again, that's what this game is all about, not simple as black and white or justice and evil. It's perfectly understandable that Joel's past has caught up with him, his death is not necessary, but sure is possible.
Don't blame the writers man to me it's such a great story I can write thousands of words about it. The ending is devastating, seeing Ellie ended up like that, but still, it felt so real, and that's why I like it.