I played Imps and I still cannot wrap my head around people thinking the empire is the good guy. The appeal to me is that they are normal people pulled into an unfair and cruel world led by people who are entirely indifferent to their suffering. The best IG stories always involve a lot of infighting.
These days I don't really tell people I am into it.
The funny thing is that they are closer to soviet ideology then nazi. It's a pitty because if you understand 40k they are the poster boys for how fucked up and insane the galaxy is.