-Alaska houses two prison stations which hold the most dangerous criminals in all of Sirius - everything from terrorist leaders to spies and assassins.
-The shipyard in Alaska is liberty's prototype production and testing facility for new military ship types. Who knows what they could be building there? It's classified. They could have cloaking devices, Weapons capable of destroying battleships in a single volley, or even tamed or cloned nomads as prototype tools of the liberty military.
True, but both the prisons and the shipyard could be easily moved. What they lose is security they gain in logistics supplies and support by having them closer.
Not to mention having them somewhere outside of nomad influence. It seems silly to let the nomads spy on top secret weapon research in order to keep other humans from seeing it, doesn't it?