nope the R. Macedonia is one thing and Macedonia is another. You had two Germanys two Koreas …now three Macedonias and just one R. Of Macedonia.

Irredentism is based on extending a country's political borders to include people of the same ethnicity or land that used to be owned by those people or country at some point in history. Germany (West and East) and Korea (North and South) are countries who are/were split because of political differences, and each of those countries were run by people of the same ethnicity. If they reunite it is because they decided to. What Greater Macedonia (and all other greater X's) are trying to do is take land from another country. Macedonia and Germany+Korea are bad examples. If those Macedonians outside of Macedonia had their own countries and decided to unite then it would be ok. But that isn't the case. Greater Macedonia advocates taking land from a country that is not related to Macedonians. It is up to those countries whether they want to give up that land.

Greater Macedonia is a "Greater" concept because it seeks to extend Macedonia's political borders to include Macedonians living outside Macedonia and land which is claimed by Greater Macedonists that don't include ethnic Macedonians. That's why it is irredentism and not a  country split in two.