Canada law is weird. They have "Crown copyright". As for Canada Post, they are required to make money, and are not required to not exploit publicly funded dataset like the postal code database. This is called monopoly.
I don't know about Canada, but the UK has 'crown copyright', and it's essentially the same as regular copyright, but the copyright is owned by the government. Places without a crown still have governments that have copyright.
There some weird things, The King James Bible, the Book of Common Prayer, and the Peter Pan stories are under perpetual unending copyright. (Well Peter Pan will go public domain when the Great Ormond Street Children's Hospital ceases to exist)
I keep that particular quirk (along with their appointed senate) in my back pocket for whenever I need to name an area in which US law is more democratic/liberal than Canadian law :)