I don't know if you read the passage in the OLB about the Gola, but there is no hint of them being slaves.
They are priests.
Hebrews had settled in Sidon among the Phoenicians and many there (or so it is said) had adopted the Phoenician religion.
This could have happened long before Babylon and all that.
The Gola were 'expelled' , or had simply settled elsewhere, or people who had fled away for whatever reason, (mostly) because of occupation by a foreign force, or because of having the wrong religious (or political) ideas in their home country (Israel).
Two terms are used to describe the Jewish world outside of Eretz Yisrael. They are very different in meaning although they relate to the same physical reality. The word DIASPORA, originating from a Greek word meaning scattering, is a value free word that describes objectively the Jewish world as a world in which Jews live in many different countries. Another word, describing exactly the same reality in a value laden sense, is GALUT [or GOLA], meaning literally exile.
The use of the term Galut or exile to describe the Jewish communities of the world indicates that these communities live an unnatural and undesirable existence. When people are in exile, the assumption is that they are living for some reason in the wrong place - it would be far more natural for them to be living in their homeland. In other words, the use of the term Galut to describe the scattered Jewish communities of the world indicates an attitude towards that world, based on disapproval and - often - of the hope that this unnatural state of affairs will come to an end, and that the people in Galut will be enabled to return to their homeland.
Edited by Abramelin, 12 January 2013 - 10:37 AM.