Naming themselves "North Macedonia" kind of implies that they are strongly connected to the other three Macedonia (administrative) regions of Greece (Western, Central, Eastern). The reason they're not going to join Greece is that there are no ethnic Greeks there, so why not call themselves Slav Macedonia instead?
[added after downvotes] what is wrong with asking why "North" is the chosen distinction? it seems that the more substantial distinction is the slavic vs greek culture and population when one considers the four regions that use the name "Macedonia"!
[added after downvotes] what is wrong with asking why "North" is the chosen distinction? it seems that the more substantial distinction is the slavic vs greek culture and population when one considers the four regions that use the name "Macedonia"!