Nope, they don't have to move but they should pay their own way instead of making everyone else pay to rebuild over and over again.

If someone chooses, for no good reason, to park an automobile across a lane on a highway and it gets crashed into, should the insurance company be forced to pay to repair/replace it? It's not all that different from repeatedly building homes/businesses in flood zones or along coasts where hurricanes are a constant threat and then demanding that everyone else ante up to pay for the damage. It seems rather senseless to me.