Yes, the city-states have been fighting all the time, just like Athens and Sparta. But they have been part of Ancient Greece.
In the case of FYROM (still the official name until the agreement gets implemented soonish), they have been appropriating the Greek identity. That was not just some individuals at FYROM, it was the whole political apparatus of FYROM since the 90s.
Yes, the city-states have been fighting all the time, just like Athens and Sparta. But they have been part of Ancient Greece.
In the case of FYROM (still the official name until the agreement gets implemented soonish), they have been appropriating the Greek identity. That was not just some individuals at FYROM, it was the whole political apparatus of FYROM since the 90s.