Literally an apartheid state and we're rooting for characters that are committed to "keeping it safe" (this means further militarizing the border between Piltover and the undercity and killing children on accident and feeling really bad about it). There's plot elements that expose how bad Piltover is for undercity citizens, but that's just the other half of both-sidesing the issue and calling it a cycle of violence. No, the REAL and IMMEDIATE threat is Silco, the guy actually committed to resistance against apartheid Piltover and even the Good and Right characters are opposed to him - to the point that they're more willing to work with Piltover, the state that has been oppressing them their whole lives and which they constantly talk about how its oppressed them their whole lives, to take him down. There's even the gem at the end where Piltover is on the verge of granting the undercity sovereignty and freedom to end the fighting, but then someone decides to fire a fucking rocket straight into the room this decision is being made in. It almost feels 1 for 1 equivalents being made to Israel and Palestine based on hasbara narratives.
I don't entirely agree with this, especially for season 1. Stories tend to have more than one theme, and Arcane has both non-political ones and explicitly political ones. It's more than just a backdrop to a story about family. The main conflict we're present in the show is political in a very obvious way, and the show doesn't hide it: plenty of runtime is used to show us characters discuss and ruminate about the the zaun and piltover situation and what they think should be done about it.
Part of the reason the end of season 2 felt disappointing imo, was that at some point they just completely gave up on those themes that HAD been a central part of the show. Nothing gets resolved and everything stays basically the same, no one in piltover has to take responsiblity for their actions, but it's treated as a happy ending, which really gives the impression that piltover was who we were supposed to root for all along, even if it felt like that was mostly not the case in season 1.