Based on the Buzz Lightyear of Star Command tv show, they seem like basically space NATO. There’s one episode where Buzz crushes an anti-imperialist rebellion on a fish people planet because the Galactic Alliance mines most of their energy crystals there, and the locals don’t like the environmental damage and the colonisers on their planet. I’ve seen kid’s tv shows try to “both sides” imperialism and colonialism, but this is the first time I’ve seen one do a “Actually the colonisers need those resources so they are entitled to take your land as they see fit”.

Also the show was made in 1999/2000 and they use the word “terrorist” a lot, it’s really funny, if it had come out just a year later they would’ve had to rerecord like every other episode.

Also Zerg may be an evil emperor, who always builds mega death rays to destroy the planet of widows and orphans, but for all we know he could be propped up by the Galactic Alliance in order to make the “alternative” to joining space NATO much worse.