To give more information, the word country is a generic term for Sovereign State.
Here is a list of Sovereign States. Which you will not find Puerto Rico listed as it own Sovereign State but rather it will be listed as an inhabited possession of one of the 13 unincorporated territories of the Sovereign State (country) United States of America.
What makes a country a country is the agreement of surrounding countries that a specific land is a country. No other country on Earth considers Puerto Rico a Sovereign State (country). It also is not considered contested, or controversial. It is globally accepted that Puerto Rico is not a country, nor has it ever been one, as before it’s discovery by Spain it was part of early Taino tribes within the Caribbean islands and then forcefully colonized, before being given as a consolation to the United States by Spain in 1898.
I think this kind of thing is great. The policies and procedures that have been developed for the internet are going to have flaws. The internet was/is a new technology in the big picture. You can’t expect the first few drafts of how to run it to be perfect. There are going to be exceptions, edge cases and inconsistencies in any system designed to run indefinitely. This is a bug, IANA will turn it into a feature.