Probably because HN is not a law enforcement agency for New York City. The law has some exceptions, perhaps those apply. Why not contact the company and politely ask for the salary range?
HN is being payed by these companies for these posts. Surely it wouldn’t be too hard for HN devs to have a running list of states that require salary ranges to be posted, and check against that when the customer submits a request. Then it will make it easier as more and more states require the bare-minimum worker right of public salaries.
that's not true afaik.