Mayor Bloomberg says a new online NRA video that labels President Barack Obama an "elitist hypocrite" is "dumb PR."
In an appearance Thursday on "CBS This Morning," the mayor said: "You have to be stupid to do that."
The video's narrator asks why Obama is skeptical of putting armed security in schools when his daughters are protected by armed guards in their own school.
The White House has called the NRA ad "repugnant and cowardly."
Bloomberg, who's a strong gun control advocate, said the NRA was itself hypocritical for coming out with a video shooting game app.
After the Newtown, Conn., tragedy, the NRA blamed violent video games and movies, not guns, for contributing to mass shootings.