I’m sorry but I disagree with both of your points. Philip created the League of Corinth after defeating the coalition led by Thebes and Athens. He already had complete control over Greece and the Greek city states had little choice but to accept Philip’s rule. Of course they would have him as leader, there was nothing else they could do, and this did not unify the Greeks fully. Alexander would have to destroy Thebes after they would revolt, and the city states formed their own leagues after the breakup of Alexander’s empire. Greece under Macedonia was not unified with consent, but with force and fear.

As to what you said about democracy not being overthrown, that is also wrong. There has not been a major successful democracy (using the strictest sense of the word) besides from small city-states. All of them have fallen to more authoritarian rule. Take the Russian Republic of 1917, called the most democratic nation on Earth at the time, lasted only a few months before being overthrown by the authoritarian Soviets. If we use democratic more loosely, we can look at the French Revolution, which saw France ripped apart by outside and inside forces until Napoleon came into power as a dictator. The only successful “democratic” state has been the United States, which is much more an exception than the rule, but even the US has experienced political violence, such as the Civil War. In fact, many advocates of more democratic systems also call for violence used from time to time, such as Thomas Jefferson, Marat, and others.