Exactly - complete evil equals complete chaos. If every Skrull is an evil, backstabbing slimeball, the empire would never have formed in the first place - the species would have destroyed itself long before it achieved space travel. A 'warrior race' is different - a warrior race implies some level of discipline, and presumably a willingness, at some point, to make strategic deals and treaties. (Look at, for example, the Skrull ambassador saluting the dying Captain Marvel as a respected foe in the 'Death of Captain Marvel' storyline - that's not what I would call evil.) I much prefer to look at the Skrulls as a warrior race rather than an evil race.