Headlights and windshield wipers

The weather here in the Great Midwest is 60 degrees and sunny while it's been raining non-stop back home in the Bay Area. Hopefully, all of the California drivers are heeding the new headlight/windshield wiper law that went into effect in July.

From the California Driver Handbook:

You must turn on your headlights if snow, rain, fog, or low-visibility (1000 feet or less) require the use of windshield wipers.

The idea that the legislature felt it is necessary to tell drivers to turn on their lights in the rain and fog raises an interesting question. Are California drivers really that dumb or do the lawmakers just think they are?