Board Thread:Warhammer 40k General Discussion/@comment-7232811-20130620224607/@comment-6078851-20140415000942

possibly, but remember that in a galaxy full of alien life tyranids are alien to the galaxy, and while they may seem amoral that's just from our perspective on morals. the hive mind is 'unfathomably intelligent' (codex quote) and it could very well be that it has morals, completely alien and indecipherable as morals by us, but morals none the less.

to stretch this idea a little further it could also be possible that tyranids are in fact the good guys, not in terms of 40k but in terms of pest control - this galaxy is awash with pesky, irritating life (that's us and the rest of the milky way natives), who each have their own self-created morals that makes every race believe that they're superior to the rest and think that their own race has some sort of 'right' to rule the galaxy. maybe the hive mind saw this in it's extra-galactic sojourns and thought "wow, not one of those pathetic exuses for a species has a single valid moral. ah well, i guess i'm morally obligated to wipe them all out."