Business Opportunity!
This is a perfect opportunity for a boat owner to start a successful business!
This is a public beach, that means you can access it any time from the water, legally.
So, a boat owner could start a new transport business. Departing from the nearest public beach and arriving at this "private" public beach.
You could run a boat back and forth all day during the warm summer months. Every half hour or so, just like a bus. Charge say $5 a head, say carrying 5 people per trip, that's a decent bit of money if you make that trip several times per day every half hour.
And the beach is public again!