YANBU.... how can anyone argue that holding a burning stick while driving is not dangerous? Eating, drinking, talking on the phone - all these things are considered to make your driving unsafe so adding fire to the mix is IMHO just about as unsafe as it can get.
Boo hoo, the poor smokers will have to stop the car and get out to have a fag - shame! Lorry drivers have to do it if they use shared vehicles and if you are a parent who smokes while in the car then frankly you are putting your kids in double danger - once from careless driving, then again from inhaling your smoke.
I'd prosecute you!