Ivan, this assumes that the child and the parent are on equal standing in the family. This is not true.
It is the assumption that the parents have the child's best interest and have a lot more life experiences. The child is still a work in process.
I'm pretty flexible with my kids but there are rules of what happens in the house. They test the rules and get consequences. It's how they grow up. Best to do it under the watchful eye of the parent who loves them.
I really don't think having rules stops your freedom of speech but that wonderful priveledge should not be used in such a frivolous manner. When you are in your own home you can say whatever you please. If it's my house it's my rules.
I don't disrespect my children and I don't expect my children disrespect me by acting like louts.
That's just my opinion.