IncGamers also got a clarification from Blizzard, shortly after the interview, saying the choice of excluding a LAN feature "is because of the planned technology to be incorporated into Battle.net," a topic they will reveal more about at a later date.
The original StarCraft gained popularity largely because of the easy LAN mode, used on massive LANs like Dreamhack or small personal networks between friends, so this is a surprising move by Blizzard.
We don't currently plan to support LAN play with StarCraft II, as we are building Battle.net to be the ideal destination for multiplayer gaming with StarCraft II and future Blizzard Entertainment games. While this was a difficult decision for us, we felt that moving away from LAN play and directing players to our upgraded Battle.net service was the best option to ensure a quality multiplayer experience with StarCraft II and safeguard against piracy.
Several Battle.net features like advanced communication options, achievements, stat-tracking, and more, require players to be connected to the service, so we're encouraging everyone to use Battle.net as much as possible to get the most out of StarCraft II. We're looking forward to sharing more details about Battle.net and online functionality for StarCraft II in the near future.