Rising ocean levels is a straw man in your argument. Tying rising ocean levels to a natural occurrence like the ebb and flow of barrier islands is, plain and simple, dirty pool. The type of thing politicians do. Are you running for office?
Yeah, oceanfront land is always changing and always has. Some of it is nature and some of it is man. If you look at Folly Beach here, you will see a mix of nature and man. The island is constantly moving, as it is a barrier island. However, the harbor jetties also redirect the currents in a way that accelerates beach erosion just south. It has really hit Morris Island, and will continue to eat away at the beachfront.
I do agree that houses/buildings should not be built so close to the ocean, but you will never convince people to follow this rule. Houses on the beach bring in big money, so they will continue to be built.