Because hackers have a wide variety of interests and often love learning about things they never heard of before.

The parent comment reminds me of how often commenters on articles posted by The Economist wonder why the article wasn't about economics. https://www.economist.com/unknown/1843/08/05/prospectus

If you don't believe this should be on HN, flagging the post would be a better use of your time and a more clear adherence to the guidelines that you appear to think are not being followed by this submission.

Because someone submitted it, and interested hackers upvoted it.