The difference is that rabies-infected humans are still human. I don't just mean physiologically. They still have active brains, know who they are, etc., even as they're acting violently. If they bite someone else, it's because that's just another "weapon" in their aggression. The rabies virus...
My position is that what are considered "zombies" today (infected by a virus) are completely different from what zombies were traditionally (corpses reanimated by voodoo). Given that the range of what is considered a zombie has expanded already, there's no reason why it can't be expanded again...