OK, I'm not going to argue this from a moral perspective because I'd lose, so let me just be straightforward.
I like reading about the imperium. As a twisted mirror of our own civilization and history, they are a fascinating and fun fictional society, who, regardless of what people say, simultaneously hold the narrative role of "good guy" and "bad guy" simultaneously. Sure, it's a fascist's wet dream, a militaristic state beset on all sides by the actual, legitimate forces of evil, but that comes part and parcel with the premise of the setting. It's also a demonstration of all the ways fascism doesn't work as the imperium trips over itself trying to secure victories.
And despite all of that, there are some of the bravest, noblest, kindest heroes gathered under its banner, fighting side by side with monsters and war criminals- and sometimes those people are one and the same, because humans are complicated.
What this quest offers is a chance to give the citizens of the imperium legitimate hope, and a reprieve from the endless war they fight. A chance to show mankind a better way. Reducing that to "imperium bad" would still be fair morally, but would definitely kill most of my interest in the quest.
Anyway I think the imperium is neat and would like to diplomance them,make them allies in the fight against chaos, and reform them from the inside instead of declaring war on them.
Not because it's the right thing to do, but because I think the quest would be more fun that way.
