Could u give more reason to why u disliked it?
I am assuming you have watched the movie, otherwise spoilers ahead.
First off, the backlash the movie is getting is wrong as well.
Critics and other people criticize suddenly that the guy who is played by Rockwell gets a redemption, you know, from racist and violent pig to the guy who is trying to help the protagonist but that is completely wrong since he is still violent (they are literally driving there to kill the guy), only that he is directing the violence somewhere else due to the letter the chief wrote him, he still has the same problems.
Those people have not understood what hte movie is actually about.
What the writer and director is trying to say is, is literally articulated by the priest but the scene gets overshadowed so it looks like any other scene but it´s about people being more than they seem (feelings and thoughts underneath and so on) and that the sympathies we might give out pretty quickly can be quite faulty, and that people are messy and not defined by their "superficial" roles, and that in the end, humanity still can connect us all (the scene where the chief spits out blood is one of the key scenes, they are literally going at each other verbally in a "war" as the chief himself called it, in the next moment she is calling him baby and trying to nurture him).
I mean in the beginning, the protagonist seems in the right, and everyone else seems in the wrong. You have the chief who is trying to intimidate the owner of the billboards, you have the racist who beats and tortures people, you have the unsympathetic guy who is screaming around and insulting people and so on, and that is opposed by a grieving mother.
It´s a setup that has been done before, the oppressor and the oppressed, at least to a certain extent, the one who seeks justice and the ones that do not really care.
And then you learn about the chief having cancer, and supporting Mildred, you leanr how Mildred treated her children and how easy it comes her to destroy someone´s feelings (in this case, Peter Dinklage´s character), you see how she is ready to throw cocktails at hte police station, you learn how Rockwell´s cop character is influenced by his mother and so on.
So in the end you have messy characters which are not good or bad but simply messy trying to live their lives, contrary to the usual narrative of good vs bad, especially in such movies.
Problem is, the characters both in the beginning and ending seem more like caricatures rather than real characters you might meet in real life, and that is important since the aim of the director is to give a realistic portrayal that is not bound by good and bad like in most stories.
Rockwell´s character of course is dumb as hell, lives with his mother, is violent and so on, like they took the character from a Dave Chappelle´s show sketch rather than real life.
Same for Mildred who is basically a compilation of the actresses most known characters except in Fargo which are completely misplaced here.
And that destroys the whole point of the entire movie really.