EI wasn't in human space until after humans moved out from Earth. The activation of the Ur Probe in the Niemandszone is what alerted the EI to our existence.
Yes, they turned up in their back yard, the security light came on and they came out saying, "get off my land".
No, the Tohaa planted ancient alien equipment on Paradiso, when the humans activated it the EI were lured to the Sphere by the promise of another sentient race to subjugate/study/destroy, which also took some heat off the Tohaa. The EI invaded our backyard.
On the flip side, most of the big nations are perfectly pleasant places to live for the average citizen, none of this learning to shoot a gun before you've been potty trained like a certain grim dark planet named after a brand of coconut water.
I like to think of it as "what flavour of grey are you?" Even what we typically consider the worst stuff isn't full out "lulz evil". For example ISS still has the mandate of protecting the citizenry (which they do, fighting organized crime and terrorists) and if Kuang Shi were composed entirely of irredeemable criminals that would otherwise be put to death anyways, yeah, I'd be 100% ok with that.
Well, considering YJ has its own definition of what irredeemable is... but, yeah. Many times ISS reminds me of the Operative from Serenity, doing the dirty work so everyone else can be clean.
Were there any 'goood' powers in infinity? IMO its just up to spotlight, YJ had it until being dehydrated. Thats all.
Are there any archetypal "good" nation states on our current Earth? Even the most idealistic nation states seem to be prone to bouts of internment camps, callous decisions by entrenched wealthy interests, horrific foreign policy meddling in other states with unexpected side effects and racist politicians stoking division etc. All powerful nations are borderline ethical/legal at home and up to all kinds of extralegal and hidden shenanigans whilst jockeying for a global place at the table. That's the governments... and then you have populations simmering with longstanding disagreements and animosity that flare up into bloody terrorism, domestic anger etc. It doesn't get any better when you project it hundreds of years into the future and start having sentient alien vegetables trolling all the factions. We can play a game... name a real world nation and we'll come up with some of the most comedically villainous things they've done recently!
YuJing is literally the only good faction in the game. They're the only culture to provide the right blend of totalitarian oversight, individual freedom, and free market capitalism (their megacorps), all bound together through the dichotomy of loyalty to the Emperor and to The Party. You might point to the WuMing and the Kuang Shi and cite them as inhumane punishments for political prisoners but I submit that in giving these miscreants another chance to serve the people is the best outcome they could ask for. Also, YJ has Robo-Kitties. So, YJ:1, Everyone else: 0. QED.
YJ guarantee a level of personal prosperity and security to all citizens, which those citizens receive, however they restrict personal liberties and freedom for this and other ends. Pretty simple, good for most, horrible for some. PanO in it's infinite liberty gives you the freedom to die in the street a penniless beggar, but also doesn't restrict your personal expression etc. Good for most, great for some, horrible for others. Haqqislam sort of balances the two but can afford to do so because they externalise all the shit things they do i.e the Silk Monopoly, incredibly corrupt corporations, assassination and so on. Good for Haqqislam! Not so great for others. Nomads say if you work you'll be free of poverty and personal restriction on expression, and also you can kind of do whatever you want, but also life in space is tough and dangerous plus we let citizens do some extremely unethical things on dubious grounds in order to pay for all this/let people express themselves. Good for Nomads (mostly) and good for dodgy unethical types in other countries (mostly). Ariadna has less of a driving political ideal and more of a "we'll do whatever to survive including some pretty horrible things" sensibility. They also desire political freedom from Sphere powers.
This is popular opinion, but Nomad type of free societies tend to be absolute hell to live in, with minimal to no healthcare and security nets, rampant poverty and exploitation, and absolutely rampant corruption and power abuse, etc. A very good example is 19th century Britain. Or many 20th century and modern third world countries. Sure, some people have it good, but most live in precarious circumstances without any kind of safety or security. Bakunin is likely best there, provided you join one of the modules, but then you are reliant on that module's rules and resources which is basically a coin toss.
If you look at the logistics and macro-economics of the setting there's a lot of things that just don't really seem feasible but are sort of hand-waved as this is how it is, and this is why, and if there's a realism disconnect between the two then it's not real so eh. With that in mind, I think it's fair to say that the setting text tells us that Nomad society is like it is, and that it's best to take that as read and extrapolate from there rather than "anarcho-syndicalist polities don't work out that way!" like this one does though, that's kind of a buy in to the setting, like Yu Jing managing to overturn Korean independence sentiment in favour of pan-Asianism which seems... unlikely.