I could understand it if the existing system were broken, but it doesn't seem to be. From what I can read, it seems to work, presumably people do get their mail and packages.
Or work around local arrangements using lat/long or plus codes or whatever naming scheme delivery companies will choose to use for your town...
Democracy (or any form of government) wouldn't last long if you couldn't work around regulations.
People have a right to share true information legitimately acquired without the constraints of governments or mobs in other jurisdictions.
Locals can't prevent foreigners from giving directions to their library or the best restaurant. Those are just facts of the world. Visitors are welcome to go discover a town then leave and tell their friends about it.
Then an addressing system is just a shorthand for that locational information. It's just a hash function or a lookup table. No one has a right to prevent others from using data structures to organize their thoughts.
All rights granted to some impose negative obligations on others. Those implied negative obligations should not conflict with other rights. Rights should promote the healthy functioning of society. Also, rights should promote freedom more than restriction.
A right to prevent others from discussing addresses without permission of locals conflicts with other rights, doesn't promote the healthy functioning of society, and creates far more restrictions than freedoms. I don't think it's a good right.
That's up to the locals. They have the right to insist you should care first about local arrangements before interacting with them.