HN removes a "how" if the post starts with it, sometimes making it hilarious.
Same reason they remove "dang" if the post starts with it, like the discussion about "Dang! Who ate the middle out of the daddy longlegs".
https://ifunny.co/picture/dang-who-ate-the-middle-out-of-the...
So if you post "1850 Bloody Island Massacre" it removes the number. But it is meant to remove eg. "13 reasons why you should impeac[...]" B/c apparently the number of reasons why is too much of a cliche or bother? Idk.
Email dang haha