>Is a regular, run of the mill R/C toy that is flown within line of sight of its operator at all times considered a "drone?"
No, but RC aircraft are also banned in DC, since they can be weaponized nearly as well as a drone can.
You are mistaken. According to the FAA, any unmanned aircraft is under the jurisdiction of the FAA. The new registrations rules only apply to aircraft over 0.55 lbs. I can't find details about the DC "No Drone Zone," but I assume the same criteria applies even though the FAA's website says, "all unmanned aircraft."
As you can see by the crazy stuff that gets posted here, and worse at political sites, we have a lot of dangerously stupid, deeply-misinformed people running around.