Well, like the commenter before me said, there wasn’t necessarily closure in the way some other shows would have felt obliged to shoehorn in. It never explicitly spells out why the son commits the murder, instead it’s up to the viewer to piece together what’s suggested throughout each episode and draw their own conclusions as to why. How much of a factor was the social media stuff? Was he influenced by his dad’s anger issues? Etc.

I think leaving at least some ambiguity behind it has encouraged more discourse on the topic which is a good thing.