Flaggers don't know jack...or the laws either. Most flaggers are the lowest paid people on the crew. I work in heavy construction for a living, I know how to properly set up, barricade and provide flagging for almost any construction situation (and if I don't I will damn well research the laws and get it right!) I would guess that close to 75% of all road construction sites I drive/ride thru are not set up properly. Your particular flagger is just being a wise ass. Ignore him and continue on as a vehicle. If wants to make a scene ask for the DOT engineer in charge or his safety officer.
Aaron