The Greater Terran United Confederation was the latest manifestation of the oldest continuous state in human civilization. Although the names might change, the humans who looked up to the ancestry of Old Earth always referred to themselves as Terrans.
As one might expect, Terrans thought highly of themselves. Old Earth was the original birthplace of mankind and even in the Age of Mechs it continued to play a pivotal role as one of the most important cultural institutions of the human race.
The stuck-up ancient clans that ruled at the top were so oppressive and insufferable that at some point during the Age of Conquest, a large amount of colonies rose up in rebellion!
Suffice to say, a lot of non-Earth humans hated the Terran elites and were just waiting for a moment to shake loose from their rule!