The article you link to is on Greek colonisation, not Greek colonialism- and there are at least three very good reasons for it.

One reason is that if you want to go back 2500 years, that certainly covers e.g. the Zulu empire and its own conquering of of neighouring tribes, the Aztec or the Inca empires, various Indian empires and kingdoms and so on - in which case the whole conversation loses its meaning because everyone has been a colonialist at some point. Of course, it's clear that the conversation is carried out in the context of European colonialism and in particular of the colonisation of Africa by European powers.

Another reason is that when we speak of the Greek colonies around the Mediterrannean we speak of new, often independent, cities founded by people originally from cities in the Greek mainland, rather than an invading, occupying force who came to subjugate an indigenous population, pillage the natural riches of its land and send it back home, as in European colonies.

Finally, we don't know of any big deportation or mass slaughter or enslavement of indigenous populations in the case of Greek Mediterrannean colonies and there is every reason to assume that many new cities were founded without a drop of blood being shed. There is generally no historical record of big invasions or military campaigns etc. leading to colonisation. The story is very different than what we call "colonialism" today.

>> Similarly, while it is true that in recent centuries Greeks have been more often the victims of imperialism than the beneficiaries of it, Greece did produce one of the greatest imperialists of all time, Alexander the Great; and the Eastern Roman Empire was for centuries one of the Mediterranean's great empires, and despite its name was for most of its history far more Greek than Roman

I have to say that I find this line of reasoning very unfair, as a Greek, given that in a different context I've been very often told that I'm not really Greek because real Greeks lived two thousand years ago, that I can't really draw a direct line of descent to Pericles, or Socrates, or Aristotle (I'm not really trying), that Alexander the Great was not really Greek but Macedonian (and incidentally my country should shut up and let North Macedonia have its name because it totally owns it) and that I look too blond and fair-skinned and pale-eyed to be Greek anyway.

In short, it seems to me that too many people have tried to tell me things about Greek history but not necessarily because they care about history, more because they want to score some points in some silly debate that I'm not interested in. I hope you recognise the danger and avoid this line of thinking yourself.

Also, your statment that Byzantium was "far more Greek than Roman" deserves a thorough debunking but this comment has grown too large already, for which I apologise. Suffice it to say that the Byzantines -and the people living in the Greek peninsula at the time- considered themselves Roman not Greek. Even today we say we are "Ρωμιοί", Romans.

Finally, regarding Alexander- Alexander's empire wasn't an empire of the Greeks, it wasn't an empire of the Macedonians, even, it was Alexander's empire and nobody else's. And when he died, it died with him because his superpower stopped working. Alexander wasn't Greek. He wasn't Macedonian. He wasn't even human. Alexander was a superhero- and like a superhero he stood above all men and did things only superheroes and demigods can do. We can learn nothing from him about the lives of ordinary people.