If the product inhibits release of virus from the cells by destabilizing virus RNA so that the cells cannot produce virus, why introduce genes to protect the outer wall of the cell at the CCR5 site?

For maximum effect, we protect cells from infection by either CCR5-tropic or CXCR4-tropic HIV and also prevent reservoir cells from releasing HIV. The vast majority of cells that are genetically modified in our product, do not contain HIV. The priority is to protect these cells from ever being infected so they provide long term antiviral immunity. Inhibiting virus release from already infected cells is a bonus that we get without additional effort.