He's not complaining, he's asking. I also do not understand what on earth this tradition has to do with hacking. Or news.
Yet strangely, hackers are finding this piece of news interesting. I wonder why? Could it be the idea of having a cat on a ship is interesting from a systems perspective? What's a ship's cat equivalent in a computer or human system? Some sort of roving troubleshooter?
Sure he's complaining. He complained in the form of a question, like you just did.
Lots of things on HN have to do with neither hacking nor news. That's part of its charm, always has been. If PG can post about the margins of medieval manuscripts, then anything goes, so long as it isn't dumb. The only sin is to be uninteresting.
It's on HN because somebody submitted it, and it's on the front page because enough people up-voted it to get it there.
That really is about as good an explanation as you're going to get :)
The cat's have finally made a through. D-Day for cats on HN :) Interesting, albeit nothing to do with HN
using a cat to kill mice on a ship is a hack. i would argue this is much more relevant than the political stories that make the front page.