Dimension portal cannot be attacked... why?

[Callinicus]

I fight the unbidden for hundreds of years. I cannot made any proper advance in the galaxy, because of those overwhelming shits, and I can't attack their first dimension portal. I killed one portal, and one other was closed by NPC. I reached the first portal several times, but it simple cannot be attacked.
WHY. :'(

https://drive.google.com/drive/folders/18xpejEFfMwv0k15c4AxpQU2XTZi7FRp7?usp=sharing

 

[Revan F]

Kill anchors first?

 

[Callinicus]

Serius? Have to destroy 200+ constantily rebuilt systems? X_X

 

[tvih]

If you allowed them to spread that far then yes, you're kinda stuck with that. In my first campaign against them it took me a few decades to erase them from the galaxy. On the second campaign the other day it took under a year - and that was playing it safe. They only ever got to make one single anchor. Joke's on them for making their entrance within my Federation, just 4 systems away from a gateway when most of my fleets were sitting at other gateway systems.