Ctrl+F for "catholicism", come up empty, yay I'll have something to add !
Having seen In Bruges turned out to be pretty essential for my enjoyment of this film. McDonagh's starting point is that people are awful, and he works from there. Cynics make for great optimists when you scratch a little, and this is what McDonagh does in his films (well, the two I've seen anyway)... but he does start from a very dark place. The other thing at play here is McDonagh's catholicism*: ) having grown up Catholic, I always feel at a distance from the way Americans typically depict it, which is to make it mostly about guilt. Not that this is inacurrate necessarily, butif you asked me the one word I associate the most with Catholicism and what I retained of it as a non-believer, it would be forgiveness. Anything can be forgiven to anyone ready to accept forgiveness, That's a powerful idea, and also a disturbing one. Anything, really ? Just like that ? And this is what McDonagh explores here... and I get why some people really, really don't care for what happens with Sam Rockwell's character here.
I think of the best films as being the ones that ask questions, as opposed to the ones that give answers, and I don't think Three Billboards has any answers to give. Not about Rockwell's character, and not about McDormand's character either. They are bad people and they do bad things: are those erased by a potential redemption ? Should they be, and can they be ? Do we even want them to be redeemeded ? Probably we want McDormand, because the root of her actions is one we can sympathize with, but by putting her on a parallel track with Rockwell, McDonagh questions our willingness to forgive one but not the other. It's not about their actions being on a same level (they are not), it's about the idea that forgiveness doesn't look at the gravity of the crime: it's not justice. And that's something that's worth thinking about at any rate.
Given that, I approach this as a fable, and don't worry too much about Lester Freamon not arresting Sam Rockwell on the spot (or McDormand later for that matter): that might be what would happen, but it's not what the film is about so it doesn't happen. It's remarkable how funny the film is too., McDonagh has to walk a very tight rope tonally here, and he mostly succeeds... there's probably something to be said about the way this relates to Fargo, now that I think of it. McDormand is the main link of course, but they're also connected thematically: you put any character from this film in the back of that police car with Marge Gundersen wondering how the hell they got there, but they'd actually have something to answer and that would be an interesting conversation. In Fargo the Coens look at what niceness and politeness can hide (good or bad), here no one is even close to being nice or polite, but there is humanity to be found: those scenes between McDormand and Lucas Hedges are key there, with the language they use and the way they use it.
8/10 (I think, haven't quite settled on a rating yet really)
*well I don't know if he's actually Catholic, but he's part Irish and it's all over this film so I'm assuming he at least grew up Catholic.