It's just an issue of overextending forces that are already stretched entirely too thin to do their job. We dont have the resource of a house military, we're a small organization, and we've got to keep tabs on nearly every system in sirius with limited numbers. If we piss off an entirely new group that hasnt had too much of an issue with us before now, we're just bringing more trouble on ourselves and limiting our ability to do the job at hand.
The situation in alpha has always called for stealth and diplomacy, not open combat.