They apologized. For something that they said would happen. Which did happen. And now they're saying they're sorry for something that inevitably happened?
EYE NO, RITE?
The finer points of this can be put up for debate ad nauseam, it won't change the fact that things happened more or less as Blizzard expected they would. They handled the situation as they expected they'd need to, and things have pretty much calmed down, now.
What really bothers me is when people drop "This isn't a single-player game!" as a justification for always-online authentication. It doesn't work that easily, folks. Consider that until I click "Open Game to Public", I'm effectively on my lonesome in a corner of some server dedicated to North American players. Until I make that mouse click or choose to join someone else's game, I'm effectively "offline", in terms of overall functionality. The only online components remaining are the server-side drop resources and the data for whatever bits of randomized events still remain. I'm virtually letting Blizzard suck my bandwidth just so it can confirm I'm not a nasty, filthy pirate.
Honestly, the only good side I can find in all this is essentially allowing for an easier experience in Internet cafés. You have to give up your current station? Fine, log out and go log in somewhere else. Your Demon Hunter's going to be sitting there, waiting for you.
If that's the case, then there's probably an alternate universe out there where a genius at Activision went "Hey, you know what? Let's ask Valve to host our game on Steam! They've got a DRM solution all patched up and generally tolerated by their consumer base - folks will love us for allowing us to add D3 to their Steam accounts!"
But, yeah. It obviously seemed simpler to just throw money at an independent server-based authentication method, because they probably got scared by how easy it is to take a downloaded Steam game's folder and crack the executable and the steam_api.dll file.
Repackage the whole deal in a commercially available installer, post this up on a torrent site, and you're done. Yeah, I can see them rejecting Steam based on that.