First, if you read my post, you would have noticed that I did say that you don’t go for the big guns right away, but keep this as an option for a “last resort”.
Then you haven’t done the best job in raising them, and you need to do some reassessment.
I will accept that premise…
IF the parents never taught the child that “flipping the bird” is a form of cussing…
IF the parents never taught the child that cussing is a mortal sin…
IF the parents themselves cuss in front of the child and/or “flip the bird” at others in front of the child (such as when someone cuts them off in traffic)…
IF parents do not discipline / correct other siblings / guests in the house who cuss / “flip the bird” in front of the child…
Otherwise, I’m sick of this whole notion of “blaming the parents” when the parents are themselves either penalized, shamed, or criticized when the attempt to discipline a child (abuse aside). I mean, you can’t criticize someone for not making a hot meal if you take away their food, pots./pans, and cooking appliances that heat the food. Come on, people!