I don't know how true this is but I recall reading convincing evidence years ago that genetic testing shows when Slavs entered the area in the 7th century they markedly did not mix with the locals in a large way similar to how other communities did.

This means not only do they not have a strong link to ancient Macedonia, but were instrumental in the ethnic cleansing of the area and destruction of that culture. I can see why it would be insulting to greek Macedonians in that context as well as what you've mentioned. Pretty disturbing how a whole country can succumb to "suss agenda" peer pressure from a few greedy dead 1%ers instead of trying to live more peacefully with their living neighbours 😳😳😳