I agree with almost everything you wrote. I place where I differ though:
If and when it makes sense to halt or ban R&D, the ban should be either narrow or temporary. An example of a narrow ban would be one on specific types of experiments that try to engineer more dangerous versions of pathogens: the risks are large and obvious, and the benefits are minor (it’s not as if these experiments are necessary to fundamentally advance biology). A temporary ban can make sense until a particular goal is reached in terms of working out safety procedures, as at Asilomar.
I suppose it depends on the level of risk. If something poses a serious threat human extinction, then insisting that a ban must be “either narrow or temporary” seems insufficient for a risk of that magnitude.The main way I see people arriving at such a position is someone starting off in a group that is uncritically in favour of progress and trying to offer a compromise that seems reasonable. Maybe someone could arrive their from first principles, but I expect that’s a less common path.