A small and minuscule bubble like the Insarka Bubble has nobody who could match a Special Voidal Knight. Even if there was one, the empire would certainly recruit them, and the chances of them staying behind are very slim.
In a situation of an attack by a powerful Voidal Monster like this, the bubble would be vulnerable.
Resources are the main currency for each existing bubble.
Every single bubble is evaluated by that simple but brutal metric. No exceptions.
Since the Insarka Bubble couldn't provide something extremely valuable to the empire, they weren't a part of the high-priority bubbles—meaning, in a case of emergency, the empire would be less inclined to help them.
And over the years, the bubble had grown to be more independent.
Less inclined to ask for help, as the answer would most likely be a no.
It was a petty decision based solely on the pride of a few.
