I think part of that silliness is intentional, at least in my interpretation of the game. The internal thesis of the game seems to be examining how far they can push the player-to-protagonist relationship until it breaks. Similar to the first game, where it was intended for players to have complicated feelings about having to control Joel in the hospital at the end doing something they may not have wanted to do but was 100% in character for Joel.

Part 2 feels like that idea stretched across the entire game, especially for Ellie. There’s a pretty powerful metaphor for addiction in the form of addiction to violence/revenge, and I feel like going to Santa Barbara shows Ellie reaching her rock bottom. The player doesn’t want this (especially after playing as Abby), Dina doesn’t want this, hell part of Ellie doesn’t even want this. It’s just the main thing she knows how to solve her problems - through violence