From what I can tell, the ground based bots don't have any onboard intelligence - they require an operator at a remote terminal at all times, more like telepresence than autonomous or even semi-autonomous robotics. In contrast, the UAVs presumably have the equivalent of an autopilot, and the X-47B referred to in the article appears to have a very good one. The equivalent ground-based robot would probably be something like a backpack scout that you could chuck into a building and have it autonomously map it.
Definitely the X-47B could be called a robot (or an autonomous, mobile robot if robot takes on the broader definition used by a few of the other commenters). I wonder how it reacts if it is engaged or damaged. Does try to self-preserve by evading or moving to a safe place without human interaction?