Why did Demosthenes refer to Macedonians as non-Hellenes?

Answer 1

"Hellene" is another way of saying "Greek." Demosthenes was an Athenian who disliked Macedonia, and is famous for his Philippics, a series of orations against Philip II, a Macedonian king. By calling Macedonians non-Hellenes, Demosthenes is basically saying they're not really Greek.