Nobody is preventing our military from using JHP. They voluntarily choose to use FMJ.
This is somewhat misleading. The Hague Convention restricts the use of expanding ammunition. Now, I understand that the US didn't sign the Hague convention, but we have made the decision to abide by it. We didn't voluntarily choose to use FMJ, we voluntarily chose to abide by a set of international laws, where one single part says we must use FMJ.
They aren't using FMJ because they are superior, ballistically. They may say they want the penetration, or something like that. My point was for the civilian, for personal defense, the penetration offered by an FMJ round is undesirable in nearly every situation.