Because they know that there are some people that would read it.
Almost every news story on a new sites yields a few replies that asks "why is this news". People who ask these questions are both stupid and selfish. See, if we review their internet history we will see they read news about UFO's, The war in Zimbabwe etc. yet anything they feel is not interesting "to them" should not be mentioned on the news.
More importantly, the same person who asks "why is this news" has a facebook page full of junk that they assume should be shared with everyone.
Its important to understand the mindset behind these comments as it sheds light on the miserable life they must lead.
In addition, people who make those comments have 0 understanding on how the news works, the news especially online banks on "views", they do not owe you anything, so if they feel posting a story about a rabbit race is yemen will get views, that's what they will post, last I checked they do not charge you to read their site.
I felt its important to break it down once and for all, the scum mindset behind the "why is this news" replies.