I've seen minor races routinely build transports but of course they never use them. I've also noticed that they often have 8 or 10 freighters and constructors filling their orbits with zero defensive ships. Seems like they could use an AI adjustment to make them a bit more difficult to defeat. As it is right now I just farm them for technology and their worlds. When the new minor race appears I gobble up that world as quickly as possible. Delicious, but it feels like cheating because they're so inept at building their defense.