that's NOT what the law says
the court erred. the cited vehicle code section (23123) specifically talks about using the phone AS A PHONE. not as a gps, not sending texts, not as a music provider. there is no law that prohibits non-minors from texting.
the law is all about semantics; anybody who says otherwise doesn't understand the law. I am a firm believer in "what the law says, the law means". This "what the legislature REALLY meant by that law" dookie from the court is disappointing. If the legislature meant NO TEXTING, they would have included it in the law (like they did in 23124, prohibiting texting FOR MINORS). If the court meant NO GPS USE, they would have included it in the law. Those activities aren't mentioned in the law, so the legislature clearly didn't intend for them to be illegal. (common sense)
the law says absolutely nothing about "distracted driving"; where the court invented that theory is probably the same place the russians keep their UFOs.