Thank you for commenting and I see your point. I tend to view media completely objectively and consider what's on the screen exactly as it is and make connections from there. It was the way I was taught, but there's no single right way to evaluate media.
I try not to read in between the lines, so I saw the movie as mainly evaluating a problem via storytelling. Not necessarily giving a solution to it.
Of course, the answer isn't vigilante violence. My view of the ending is more from a fiction writer's perspective and seeing how it brings back the beginning/using Chekhov's Gun. I understand how it could be interpreted as a promotion of vigilante violence. I didn't think it was saying that was the only solution, but it was a way to end this particular fictional story.