I thought it was so that they could determine which weapons could be used offensively and which weapons can only be used defensively, and so they don’t leave the UK open to legal challenges in the future. I believe from what I read there is a precedent for doing this from another case the UK was implicated in.
They have stopped issuing licences haven’t they? I like to believe that things are officially on hold until they have that clarification, but maybe it isn’t politically sensible to make a big song and dance about it at the moment?