That was close to my experience when I roadraced motorcycles a few years back. The beginner class was by far the largest field, and the riders were most likely to pull bonehead moves that put other riders in danger.
Seems like lots had visions of professional careers dancing in their heads or something. Whenever possible, I would try to ride in any other group — the experienced racers might have lapped me about once every 4-5 laps (!) but they did so without trying to run me off the damned track.