[coldtea]

Because it was voted by HN users.

What does your comment has to do with hackernews?

If you were a frequent here, and represenative of the HN crowd (something which your question implies being), you'd have seen the same question time and again, and always the same answer posted from HN guidelines:

"On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity".