Why can't comments on Hacker news follow etiquette of staying on topic? People here respond to the top comment directly with a point that's not even closely re

Why can't comments on Hacker news follow etiquette of staying on topic? People here respond to the top comment directly with a point that's not even closely related to the top comment. And then everyone else follows. If you're making a new point that's not gaining from the chained comments feature or directly conversing/adding on to the person above you, just create a new comment.