1. How long the aliens are in Sirius? From that, another point:
2. Why is your diplomacy set as is? Because if I got it well, aliens appeared in Sirius after they jumped here through super wormhole. I assume that in Omicron Lost based on fact that mother base is here. Ok. But they don´t know anybody here, they don´t know who live in Sirius. So you can set diplomacy only after you met somebody. For example you meet Nomads, they started to shoot on you = Nomads are hostile since then. But you have in diplomacy factions that you can´t met and even don´t know about them if you are staying only in few Omicrons. Like Hessians, Bretonians or Gallics, where you met them, how even do you know that they exist? And same question is about Corsairs, why are they hostile to you?
If aliens are not here for tens of years and explored whole Sirius they can´t know who is their friend and who is enemy (by the way - Gallia is problematic issue at all, because even a people from Sirius don´t know about them much and the path to Gallia is opened only two years inRP). There is written for example as unfriendly "Liberty Government (Note: seeing them as bad bad corrupt bad government which we hate seeing.)" To make this stance and knowledge, you have to live in Liberty for some time. Or it´s based only on what for example Zoners (which probably contacted the aliens as one of the first) told them about Liberty.