I think we can blame the court for this one. "Using" means using. It's not specific, but the court reinterpreted it to be more specific for some reason. It's essentially impossible to write a statute to defend against this since you can't depend on any particular word to be load bearing.
Even if you use comprehensive forward-looking language, the court can choose to strike any part they don't like under the guise that the current situation didn't exist at the time of the drafting.
The law could've been written like "While operating a motor vehicle, it is unlawful to use a smartphone, tablet, or other hand-held device, regardless of the activity being performed on the device."
I agree the law should attempt to be specific, but I have to point out that this is still quite ambiguous!
Is it permissible to dictate/listen to text messages on my handheld smartphone, so long as I don't hold it in my hand? Can I click "next track" on the steering wheel, but not on my phone screen?
What about smart watches? They are not handheld, but they are equally distracting, if not more so than a phone because their screens are so tiny and fiddly.
"While operating a motor vehicle, it is unlawful to use a smartphone, tablet, or other hand-held device in a manner that requires physically touching the device, regardless of the activity being performed on the device."
California courts do whatever they want. Did you know that CA banned affirmative action by statewide referendum? And gay marriage? CA is the least democratic state in the country, by a wide margin.
California voters later enshrined the right to gay marriage into the state constitution by a statewide referendum that won by larger margin than the earlier anti-gay marriage referendum won by.
Even if you use comprehensive forward-looking language, the court can choose to strike any part they don't like under the guise that the current situation didn't exist at the time of the drafting.