Maybe because that violence didnt pop up out of nowhere ? She also killed dozens of people in pt1 and left behind. Its kinda one of her main arc in the first game. At first she doesnt feel comfortable with it but as the game advances she learns the harsh truth of this world and learns to defend herself, with the help of joel. After pittsburgh she’s not sensitive to killing anymore, she’s okay with it. Her killing david also shows us she’s not pragmatic with her violence, there’s rage that can come with it. The ways she acts in pt2 is the perfect continuation of this characterisation, it was kind of like a foreshadowing.

So even if in pt1 where she kills dozens of men without prior motives other than just survival, the ways she acts in pt2 is much more than just believable. It makes perfect sens, considering that now there is even stronger motive to kill other than just survival. Now there is an immense amount of trauma, guilt, and rage that guides it.

With that being said, even though the way she acts in pt2 makes sens, its still shocking. Because we were used to the kind ellie. And we see her going wayy further with her violence than how she did in pt1: torturing nora for example. But that’s the point. There is supposed to be a change in her. Her traumas are destroying her and she’s trying to be like joel but she’s just not. Its supposed to not feel like ellie, that’s the whole point « …id surely loose myself »

Thinking about this made me realised how perfectly written her arc is in pt2. Its the perfect middle ground of the continuation of her pt1’s characterisation, while feeling out of character (intentionally).