Gnash! Wail! Gasp! Etc!
This is sort of a retcon. I say "sort of", because I don't think it's ever been stated that the faction is all-male, it's just that no one's mentioned female members before.
Obviously the thing that's annoying these very mature and sensible people is the change to "established" canon and NOTHING ELSE, so I imagine that they are also furious about:
- Squats.
- The origins of the Necrons.
- Space Wolf commander Leman Russ.
- The Sensei.
- The half-human, half-Eldar chief librarian of the Ultramarines, who may also have been a tennis player.
- Where Squigs come from.
I don't always agree with Games Workshop's decisions -- release your old books as print-on-demand, you cowards! -- but this is glorious. Well done, GW.