The disparity between news reports and reality seems bigger then the supposed disparity between missions and reality to me, to be honest. Every time someone shoots off the old "Capsuleer fleets are catching up to the Empires!" line, everyone is always quick to jump at them and remind that they all have thirty bazillion titans or whatever lying under the sofa. But at the same time, a sighting of a couple battleships is a international security risk, and an incursion of 20 or so is an invasion?
It makes no sense. There's no way to reconcile the two ideas without radically warping your understanding of the game world to accommodate it.
As for the canonity of missions, I'll echo what everyone else says: While it's silly to say that hundreds of Capsuleers are literally foiling the exact same Gallente gate construction plot every day, and citing close specifics is kinda akin to being one of those people who talk about personally killing Arthas in WoW, I think it's equally silly to act like that whole part of the game just plain isn't canon. You can't just dismiss actual (written) content as completely nonexistent on every level simply because it's a bit contrived. If we did that, we'd be considering half the game nonexistant.
I think it's also kind of crappy to push this line on other players. I've seen people who don't really like to PvP much and do a lot of PvE to support their faction be brutally dismissed in character as being just ~crazy~ when they bring it up in public, and, without even taking it OOC, being simply told that the stuff the game they do just doesn't happen. That's not cool.