This irritates me too, and I see it all the time. No, a sliver of metal or a piece of plastic being excited by an indiscriminate outside force is not a robot.
If there's offboard sensing and control systems which can maneuver the particles individually then you could make a case for it. If you're just jiggling them with a magnetic field then no.
The reason you're seeing it all the time is probably because roboticists are very excited about using external magnetic fields to create smaller designs that don't require carrying a power source, without worrying whether those are still "robots".
