The zip code issue is not unique, and nor are the post codes broken. Postal codes are for mail routing. They get your mail to the correct mail centre for sorting and distribution. There is no need for the postal codes or mail centres to align to rational boundaries like states, counties, localities, suburbs, or any other reasonably controlled, surveyed, and relatively consistent dataset.
The real perversion here is a software developer deciding to use postal codes, which were designed for something entirely different, and which are maintained by a postal carrier, to locate and veryify addresses physical location. They've not recognised that within a post code could exist multiple towns, or towns in multiple states, etc.
> rational boundaries like states, counties, localities, suburbs, or any other reasonably controlled, surveyed, and relatively consistent dataset.
Those boundaries aren't necessarily rational either.
But not only does your post code not reference your political boundaries. Your postal city may not be a political city, or may not match your political city. I've lived in several places where I needed to write the city that the post office serving my house was in, if I wanted to receive mail. It's really more of the name of the post office, there are plenty of post offices in unincorporated county land, which doesn't belong to any city.
I live in unincorporated San Mateo County aka West Menlo Park aka Menlo Park aka University Heights. The zip code is the Menlo Park zip code. The nearby branch post office, outside the city limits of Menlo Park, names itself West Menlo Park but shares the same zip code as Menlo Park.
I use Menlo Park for my mailing address incuding zip so no credit card problems. The city library does think I am a Menlo Park resident even though I don't pay their taxes. Other city services may check more closely.
To further complicate matters, I live one block beyond the Menlo Park city limits, but within the boundary of the Menlo Park City School District. So our street is its own voting precinct since we vote for city school measures but not for say, the Menlo Park City Council. And maybe because it was too small, 20 years ago, our precinct lost in-person voting on election day.
One final boundary condition: Atherton, Menlo Park, and unincorporated San Mateo County all lay claim to parts of Valparaiso Avenue. Atherton has one side of the road, Menlo Park the other until the entire road becomes the County's. The construction standards for the three sections vary. Atherton, not surprisingly, used the best materials and methods when the road was rebuilt. On the other hand, recently, the county was the first to repave its part of the road.
The real perversion here is a software developer deciding to use postal codes, which were designed for something entirely different, and which are maintained by a postal carrier, to locate and veryify addresses physical location. They've not recognised that within a post code could exist multiple towns, or towns in multiple states, etc.