The applicable California law was written in the days of the Wild West. Poker was considered "immoral" at the time, so the courts decided that they would not intervene in gambling disputes. If someone had an ace up their sleeve, that was on you and your trusty Colt .45 to resolve the issue.
Of course, today nobody is pulling a gun in a card game. Poker is a family-fun game. Televised, shared by millions, and taxed by the State of California. Unfortunately, like many old laws, it sits unchanged in a dusty law book while time marches on.