I think their reasoning is probably that:
a) they don't want people to hold off buying stuff now because new, better stuff is coming next month.
b) they're still hoping against hope that if they can scare enough bloggers, people won't post negative reviews about their stuff online.
c) if they can make it so that the only way to find out about stuff ahead of time is through White Dwarf and their website, people will go there, rather than to sites that talk about other companies. GW seems to want to act like the other companies don't exist - which does work, hence loads of GW players know nothing about any other systems.
All of this makes them seem pretty unpleasant to people like us, but then we weren't going to buy any of their overpriced models anyway...