We are finding out, by talking and describing to each other and comparing our traditions, what simply is a bad habit and what is universal consensus across our species. It makes pretty obvious which laws are only in place to terrorize and which are meant to ascertain peace and prosperity and mutuality for the community.
There is only one rule necessary from which all willing and wanting can be derived, IMO: the "Golden" one. Once you have that, you don't need another one that forbids to go and kill someone, just for example.