It's gone beyond landing boats, it seems to me.
Of course that kind of nuisance behavior is not right. Neither is it right to shut down the beach all together. They get their property and nothing less, the public gets access to the state owned land and nothing more.
I would think anyone who owns a home on a beach is going to have creeps disrespecting their property. And that stinks. But there are offensive people everywhere. There are also self-respecting people who respect the property of others.