The government of Greece at the time wasn’t really a colonial power. It was the Sublime Porte, AKA the Ottoman Empire. It was an Empire in the classical sense. They conquered regions and attempted to rule them as a part of the country, as opposed to forming extraction based economies.

Now that doesn’t make them benevolent- like most empires they were backwards and they were later called the Sick Man of Europe for a reason. But colonialism is actually one of the major reasons the Ottomans declined, as it allowed Europeans to get the resources that traditionally flowed across Asia Minor via sea lanes, and in some cases they even conquered the origin points ending what was their traditionally largest source of income.