From what I'm gathering reading around the internet, PC/PS3 players aren't upset they don't have Dawnguard, they're upset at the awful communication from Bethesda.
For the record, I think PS3 users have the most reasons to be upset. It's been 16 weeks (!) since we've had an update. Considering the PS3 has had the most issues, that's....a really long time.
Awful communication?
More like
what communication?
I'm feeling pretty paranoid at this point that they really are going to pull a ToV and make 2/3 of the world hate them for a quick paycheck. I don't want to believe it, but I can't help it. There just seems to be no reason that I can foresee about why they'd say something like "we haven't announced it."
If you think about it, they have already said they aren't releasing it on other systems simply by not announcing it. I have no idea what exactly this is supposed to achieve, other than frustrating their customers. If they'd give us some kind of hint or information, we'd be able to relieve our frustrations...but they have given us no such recourse.
So really Bethesda should be bashed for this, because they need to learn that this DOES frustrate us, and that they SHOULDN'T do it. If no one says anything, they would think that their customers don't care.
Which isn't true. We do. With a game that's as successful as Skyrim, it's totally crazy that they'd think that 2/3 of the people who own it don't care about its DLC.