If it works and HIV resistance installed in a population, then it opens the possibility HIV could be then could become an effective bioweapon for that population.

1. If it works, you'd need to wait 50+ years until most of your population was immune. You'd have to hope that in that time HIV vaccines/cures aren't developed.

2. HIV would make a terrible bioweapon. It's difficult to spread, takes a very long time to incapacitate people, and there are generally effective treatments.