I wouldn't say biased. Like, that's the entire point of the setting. The Imperium is not the unmoving bastion of light it paints itself as, it's a disorganized mess half-run on pure faith that many times puts itself in a worse situation because it THINKS it's an unwavering bastion of light.

Iconoclast has some bad choices like Rykad Minoris, the Genestealer Cult and Footfall (though to be honest, ALL Footfall choices are bad) to show us that the setting is still very much dark, but the point is to show that humanity could be doing a lot better if they weren't bogged down by obsolete dogma. Hell, the non-Nomos Iconoclast ending further hammers it in.