The network gear I manage is only accessible via VPN, or from a trusted internal network…
…and by the gear I manage, I mean my home network (a router and a few managed switches and access points). If a doofus like me can set it up for my home, I’d think that actual companies would be able to figure it out, too.
But this is USPS, which isn’t an American company, it’s a US independent agency.
Their mandate isn’t (AFAIK…) to make a profit, but rather to serve the mail requirements of a very large country.
Personally, my experiences with USPS have been generally positive, from passports for infants to free change-of-address forwarding service to tracking down quasi-scam products from Amazon. YMMV though.