Since you included the relation in your post, you also gave the answer. The standard map rendering uses the name field for each country. This field contains the name of the country in the (main) language of the country.
The standard map does not show the official UN name or the name in Dutch or …
I did a quick bit of research on why the choice of name might be sensitive, and my guess is that the OP’s Macedonia is the Greek one that caused the UN name to be changed. In that case, his best solution is to find, or sponsor the production of a Greek language rendering of the map. There is a tool for doing this on a small scale at http://mlm.jochentopf.com/, but to serve the whole Greek community, someone needs to donate server time. He could also sponsor the production of an UN:en rendering of the map (the multi-language map, above, doesn’t seem to recognize UN as a language, but does recognize el)…
The general policy for the name tag, and the default rendering is to use the name as it is actually used in the place that it names, with a preference for using what appears on road signs and name boards.
Missed that. It seems to have happened within edits 13 through 62, which have been redacted. I’m not sure how you can have redacted edits that introduce real changes. The changeset for version 63 is from the redaction robot.