Your idea sounds nice, but it doesn't really make sense. Consider that terrorists can easily do GoF and release the product - no research necessary. On the other hand, when scientists do GoF research, our virological knowledge may be furthered, possibly with applications to making new vaccines and similar.
That isn't a sufficient reason not to scrutinize the process by which this research is conducted if the origin of the virus is from the lab. It matters if this virus was of natural origin or was leaked from research going on at the lab, altered or not. It should inform us better on safety for researchers, or caution us about avoiding contact with certain animals and help us learn more about how viruses jump from one species to another. There is valuable information to be discovered in the investigation of the origins of this pandemic. It's only rational to be interested in that if we want to be better prepared to prevent future pandemics.
