Parents are responsible for their kids under 18 over here, too. But that’s not what the “feet under table” argument is about. It’s about “we pay, and you do as we say, down to every little tidbit of opinion or back-talking”. Basically, the teenager hears “You’re not wanted here, the earlier you leave the better, and in the meantime, because of the huge burden you are, you are a prisoner with no free will.” Of course the teenager rebels against that with “I didn’T ask to be born” or similar.
If you sit the teen down and explain what laws apply and why there can be trouble, it’s a very different situation than the “feet under table” argument.
That doesn’t mean you have to treat the teen like a prisoner for having an opinion different from you, or wanting to have a life, too.
Of course the teen in the OP isn’t rational at the moment. One problem esp. children have is that they don’T know clearly what their feelings are, so they have difficulty articulating them. That’s why talking in the right way (professionally) is important.
Talking at a teen, instead of with him, is a world of difference. If the teen doesn’t trust what his parents say, he won’t talk honestly to them, because he doesn’T believe they will care, or that it will make a difference. And going to a professional won’T be helpful if the teen believes that the shrink is there to make him go back on track and obey, instead of fixing the problem in the whole family.
Try to see things from his perspective: you feel you are treated unjustly and unfairly by somebody who has control over important aspects of your life (and he’s already partly adult, so he will feel that he can make some decisions of his own). Instead of listening to your complaints, you get ordered to solitary confiment, and there is no higher authority to appeal to. Maybe you have had a boss who simply would not listen to your side of any problem? That’s probably how the teen feels, only he can’T quit the job and walk away. He’s doing the only thing possible for his self-respect, and I’m sure he doesn’t like this, either. But he doesn’t want to give in to unfairness (from his POV), and so things continue.
A trained professional or a mediator is good if the parents accept and understand that they might have done something wrong (not in the sense of using too little discipline, but in the sense of insulting another human person, or belittling him, or otherwise being unfair.)
Have you ever apologized to your child because what you did was wrong, like calling him names or belittling him? If not, there’s no true respect. No parent can be a perfect person 24/7; but how shall a child learn to control his temper and respect other people if he isn’t respected? It impresses a child much, much more if a parent admits a mistake “That was out of line, I shouldn’t have called you an idiot, I’m sorry”, then if a parent pretends to be above the rules and infallible. Kids will eventually realize you’re not, and then they will losse the artifical respect for you.