The writing for the end was horrible. I suspect they basically wanted to figure out a way to keep Abby alive for what I assume is the expected TLOU3, but logically nothing makes sense. Abby killing Joel because of Joel's actions in TLOU I can understand. Joel dying, while shitty, is understandable: Joel did a lot of bad things to Abby's community and destroyed her "normal life". We empathize with Joel's actions because we see it as "parent protecting a child", but from Abby's perspective, Joel was a terrorist who took away her family and left her life in shambles. Abby even "tempers" her revenge...she doesn't start murdering Joel's entire family. In her eyes, they're even I guess. Abby has her "revenge". Then Ellie wants revenge, which is understandable. So Ellie basically wipes out Abby's new family...then spares Abby, who escapes. Ellie doesn't have her revenge, but still essentially loses everything (Dina leaves her, she loses her musical connection to Joel, still killed a bunch of people). It honestly is an odd tone: Abby and Ellie are essentially punished equally, even though Ellie decides to make the "moral" choice, which is questionable because now she assumes Abby won't seek revenge for everything Ellie did, putting ELLIE'S loved ones at risk now? "Breaking the cycle of violence" doesn't happen because it requires BOTH parties to break the cycle. One does have to take the initial "good faith" step to reassure the other side, but that is with the presumption the other side wants to stop as well. Ellie is now putting faith that the other side won't seek revenge, that they won't try to even the score by killing Ellie's loved ones. Joel didn't want to take that risk in TLOU1 (rightly so, they -would- have come after Ellie and put Joel's loved ones at risk). Ellie not doing it to "not repeat the sins of the father" is a massive gamble and leaves the viewer frustrated and angry that Ellie is now in an even worse off situation. Killing Abby, then losing everything and wallowing in the actions she pursued, while grim and dark an ending, at least gives some manner of "closure" to her story. Tarantino loved the movie "Lady Snowblood" for that reason.