There is no law in CA that forces private property owners to allow public access across their private property to a public beach. Whether the public can be on the beach is not in dispute in this case, it is whether they have the right to use a private road to get there.
The road always had a gate, and the previous owner do not keep it open all the time, and the previous owner charged for access. There was no easement and the judge didn't rule there was.
The law was obviously on Khosla's side or the judge wouldn't have had to go through legal acrobatics to get to her decision. She literally said the closing a gate for 24hours a day (which already was closed some of the day), was "developing the property" and needed permits. That is insane judicial overreach, and a blow to private property ownership.
Should all beaches be free and open to the public? Ideally yes, but the state should retroactively be taking property from rightful owners to make that happen.
The conclusion of the Overview of California Coastal Access Law states:
While the public beach in California includes at least the portion of sand up to the mean high tide line, the actual public beach varies from lot-to-lot and break-to-break up and down the coast. California’s coastline is subject to many competing interests, and coastal property owners may face loss of their exclusive use based not only on their acts or omission, but those of their predecessors. There are steps they can take to protect their interest against the permanent creation of an easement, but these similarly involve a loss of exclusive use of the property in question. Similarly any development or use requiring a new development permit may result in an easement or expensive grant of similar property to the public. Given the state of the law, property owners rights are severely limited and only the most careful planning and use can allow the coastal property owner to maintain a fee interest in the property free of easements and other encumbrances.