There is only one Creator, true and every individual has been subject to a specific spiritual, come religious instruction that was applicable to their time, their capacity and their need.
So individuals do not set their own rules, even if they imagine they do, apart from mental illness, and most people without Christ have some other Christ like Teacher, such as Buddha, Krishna, Moses, even all the indigenous peoples have their own Teacher and a very specific set of spiritual / moral codes.
Jesus is only essential for Christians, others have their own legitimate path to God.
