Hello @ftrebien
The link you are citing is out of context. And having studied some of your previous editions, I would kindly ask you to be open to suggestions, because you have some concepts mixed. (https://www.openstreetmap.org/changeset/133341838, sorry, but that is not an unclassified road).
The classifications in OSM are, with the exception of motorways, a matter of the purpose that the road serves in a given reasonable big network. But that doesn´t mean that, given a reduced place (a small island) all the categories immediately go up one or two steps.
So, the examples that this paragraph gives, are the trans-Amazonian Road, which, despite its quality, connects big cities, some of them with millions of inhabitants.
Both Russian examples are roads that connect big cities in the far east.
The Madagascar example refers to a road that connects dozens of towns in the northern part of the country. And serves a wider network.
The Sudan example is one of the most important roads in the country, despite its quality.
King George's island reportedly has maybe a hundred inhabitants. spread in several settlements. There are mines on this planet with more inhabitants.
So, we will all understand that mapping the roads that connect them as tracks or even paths is wrong because they serve a purpose in this very little network. But secondary is a huge overrepresentation. Tertiary is, maybe, an appropriate category. Some will say unclassified. Take into consideration that secondary implies motorcar=yes.
Sorry for the long response, my only intention is to help, and the time will come when a combined effort will have to be made in Antarctica because some other editions here are just wrong (not by you).

