The player isn't an equal to the major factions and it's fine for them to try and stomp you out.
Until player has multiple size 8 colonies, making the player bigger than the biggest major faction. With good management and Free Port, it does not take too long before player can breakout and match or exceed the major factions, yet the majors still treat the new greatest superpower like a minor.
Meanwhile, they do nothing to stop pirates and let some of their worlds decivilize.
Stupid stuff like this makes me want to let the pirates decivilize all of core just to make core worlds stop sending expeditions. (If pirates are too slow killing core, stealth raiding their worlds myself can get the job done.)