Maybe other people did, they just chose to talk about something slightly off topic.
There is nothing in the community guidelines about having to stay on topic and to only talk about what's on the article.
There is however:
Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.
Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that".
Maybe other people did, they just chose to talk about something slightly off topic.
There is nothing in the community guidelines about having to stay on topic and to only talk about what's on the article.
There is however:
https://news.ycombinator.com/newsguidelines.html
What makes you say that?
Everyone else just comments and assumes based on the headline