Why didn't greece become a colonial empire?

Because they had to fight Turkish invasion and at one point the entire Greece was taken over by Turks. Also, after losing their own country, I don't think they would want to colonize other countries as they sympathize the experience of being colonized.

It didn't exist. Up until the nineteenth century, much of what is now Greece had an ethnically non-Greek population. Athens itself was a village which was entirely Albanian, the same was true of much of the Peloponnese.

It did. Haven't you heard of the Ottoman Empire, you numpty? Ottoman was the name of the ruling family.

During the majority of that time period, Greece was under the control of the Ottomans. Greece wasn't a nation until the 1800's.