"Why then can we not add reasonable restrictions to 2A?"

There are an abundance of reasonable restrictions on the 2nd Amendment already Winston. As in, felons, the mentally ill and drug users may not own guns, background checks are required for purchase, as well as a myriad of other restrictions on what types of guns can be owned, where and how they can be carried, etc., etc., etc. I think if you were honest you would admit what you're really seeking is for the 2nd amendment to become so heavily restricted that it is effectively abolished.