I just remembered a main criticism I saw a lot after the movie came out. The one where people were pointing out that the movie "took time to establish that the demons are people too and we need to accept our flaws" only to have the girls kill all the demons in the climax. I guess the argument is that they should have tried to find a way to reason with the horde of soul-stealing demons and their all-powerful, all-evil overlord instead of jumping right to the slaughtering.
And this is where I think people get a little too wrapped up in the demon = some kind of marginalized person symbolism. There are elements of it and Rumi as a character is good representation for anyone who views themselves as some kind of outsider looking in. Whether it be a mental illness, race, body image, sexual identity... Marginalized people saw themselves in her and that's valid! She definitely was created to have similar struggles. But where we have to be careful is isolating that symbolism to just her character (and Jinu as well) and ignoring what literally every other demon in the movie was like. When we're looking at our two main characters, and especially Rumi, we can see their struggles and their remorse and self hatred and we can sympathize. We can see it as "they're demons, but they don't want to be/aren't evil like other demons" and it's easier to attach our own feelings of being demonized by our own society for something society deems as "wrong" with us.
But in the bigger picture of the world in this story, demons are bad. Like, bad bad. Even if many of them are victims of Gwi-Ma's manipulation, we aren't shown much of that. Aside from Jinu (and maybe that one flight attendant demon who had to go back to Gwi-Ma alone), we don't see a single demon show remorse for anything. Many of them actually seem to revel in what they're doing. Even the cute crying one everyone loves wasn't crying because he feels bad for taking souls: he was crying at the idea of the demon world losing the war against the Hunters. He cheered with everyone else once the Saja Boys starting pulling souls into the underworld.
And yeah, it doesn't help that the only demon we spend any length of time with is Jinu. And I guess an assumption could be made that maybe it's all an act and all of those demons actually feel really, really terrible about killing countless people. But we aren't shown that. We're shown demons cheering about people's souls being devoured by an evil bonfire and gloating about how many of Huntr/x's fans they're going to eat. We're given one demon who feels bad, and still goes along with the mass murder anyway.
(And don't get me wrong: I like Jinu. I thought he was fun and charming and has a good platonic relationship with Rumi. But he still did that. And if we're going to narrow it down to thinking only of the emotional impacts to our main characters, he also took information Rumi told him in confidence and used it to expose her in the most demoralizing and embarrassing way possible. Him dying at the end was the narrative giving him a balanced end to the crimes he committed, and even then, it doesn't feel wholly satisfying because now there's no follow up. He's dead. Rumi can't confront him about anything. None of the human victims will see any sort of apology or payment for what he did. Even Mira and Zoey can't yell at him they way they probably want to.
This is kind of like how Darth Vader dies at the end of Return of the Jedi (spoilers if you live under a rock). For the whole trilogy he was The Big Bad until an even eviler dude showed up. But he was still responsible for countless death and misery, even blowing up a whole ass planet. But he was also a victim of manipulation and bad choices. We can sympathize for him, and we can cheer when he does finally do the right thing and save Luke from the Emperor. But he still had to die, because he did so many bad things. He could have lived but he either would have been executed or thrown in jail for what he did. There would have been a lot of people who wouldn't see his redemption the way Luke or we the audience saw it. So the story would have had to suddenly mind wipe those people, or ignore them and say their pain wasn't valid. Bear in mind, his daughter Leia would have been one of those people because it had been her planet he blew up. Him dying solves that moral dilemma, because he's gone. He faced "the ultimate punishment" and he is no longer around to cause any more pain.)
So yeah... There's a reason the climax was focused on just killing the demons. They were dealing with an unreasonable evil who just wanted to be fed a stadium full of innocent people, and his army of monsters. To have the girls suddenly start a therapy session for creatures who at no point ever showed that they would respond well to it wouldn't have made a good ending. We didn't even get the cop-out "Gwi-Ma died and all the souls he ate suddenly appear again" trope a lot of kids movies tend to do in these situations. As far as we know, those people are dead. And demons are the reason they are.