I suspect that they are doing a pre-launch worst-case-scenario drill to see what would happen if they came under some sort of a DDOS cyber-attack! They get one in-house team to attack and another to then defend and try to keep the connection up. As of now, the latter team is losing.
You see... they can get valuable information from this and may become more prepared for this type of scenario should a corporate gaming competitor (i.e. Microsoft) try to embarrass them when the game gets out of beta. Or, perhaps a member of some triad cyber-gang is about to lose a wager on a match and so he has his friends try and pull the plug on the whole network?! If you are Blizzard, you have to be prepared for these kinds of things!
And, at the same time, they can see how many people will keep trying to play despite the futility. They can see what this event does to their ratings system perhaps. But, mostly, they can generally try to figure out how to deal with similar problems when they pop up later. This is all very serious business people -- mucho dollaro$. Reputations at stake, the future of E-sports! The joy of countless millions fantasizing about being an intergalactic Napoleon. Yes, all this is at stake.
So... put on your tinfoil hats people, we're in for a bumpy ride. This last month is going to be hell.