My thoughts on that GamesPoet are as follows. Either;
a. No one proof reads the codex book and these idiocies are in print before anyone can do anything about it, so they have to go along with it.
b. They market the game to new gamers who don't know/care about the old fluff and are doing all they can to big it all up so people spend their hard earned cash on the new army.
c. They hate us older gamer and want to upset us deliberately.
c. Some combination of the three above.
What I suppose is ironic is that many of us older gamers complain when they recycle fluff from edition to edition!
Proof reading doesn't mean its being read for content. Newgamers might not know the old fluff, but they aren't likely to initally care, and evidently the powers that be at GW dont' seme to care either. I seriously doubt they hate old gamers because we spend money, too.
As I think about this more, its probably just one writer putting together what he thinks is good, putting his own stamp on things so to speak, and doing a bad job. Probably whoever he reports to isn't paying that much attention to the fluff side of things, since the real money makers are the figures, rules, and supporting materials, not the fluff. However, if someone is actually monitoring the fluff, they need to do a better job as well.