You could clearly call the caste system of the Imperium (not to mention its record on Sophonts rights - or lack thereof) and a few of its actions over the centuries as well and truly repressive and some outright horrendous.
Each of the large interstellar governments can be painted in a certain way depending on who is offering the evaluation. The Solomani have an element of neo-Fascist and neo-Soviet Stalinist thinking about them. The Zhodani have a more classic Communist mindset, in parts. But the Zhodani could also be seen as a progressive society devoted to the health, satisfaction, and mental well-being of its constituent citizens and whose main goal isn't expansionistic attempts to gobble up nearby neighbours. The Solomani could be seen as industrious rebels struggling against larger neighbours bent on their destruction and forced to take some unpalatable steps along the way.
For maximum benefit, it is nice to bring out the nuanced nature of the various subparts of humanity - play on some of the stereotypes, but show where they are simplistic and inaccurate. A deeper look will often reveal something far more interesting!