They added stock huge hull ships for the other civs, Terrans were the only one to have them. All the civs had starter blocks but that was all.
Okay, now I see. I was confused because they didn't add huge hulls, they just linked the huge shipdefs to the large ship models. This is why the icons are wrong, because the Alterians and Iridians don't really have their own huge ship designs.
The interesting case is the Drengin, who have designs for Avatar, Dreadnought, and Fortress, but not for Titan. They got the same treatment as the Alterians and Iridians. This means, that even though they have 3 stock huge ships, they aren't using them. Instead they are using the large designs (Battleship, Cruiser, and Destroyer). This also means that the Drengin Avatar, Dreadnought, and Fortress use the icons for their huge designs, but the actual ships are using the models for the Battleship, Cruiser, and Destroyer.