Is there a problem with ISO3166 denoted information in general or is there a specific US issue here? I would think ISO code denoted tzdata was a public good in some sense.
All the legacy time zones were moved out of the default zoneinfo install. It’s not a us-specific issue but the legacy US/ timezones remain in widespread use, and they stop working on Debian 13 ootb (possibly Ubuntu noble as well?).