I'd say this was a perfect Show HN, a small piece of actionable information which is slightly amusing at the same time.
It's a Tell HN. Show HN is for things you made.
Good question, what would be a better way to post this?
Just a simple post with no "Show HN"?
I know I'm not showing a product, but I'm still "showing" something I found.
In the past, some people have used "Tell HN" for things like this.
thanks, done it.
Because it's a cool hack, it's new and he is showing it to people on HN.