The term is "ignorance", or more specifically, "spiritually ignorant". Two people are married by their own words of commitment, not by the power of any religion.
Perhaps Mandela's move was political.
However, each religion has its own spirits. Participating in one opens doors for those spirits to enter in.
There is no need for approval from the state, or from any denomination, or from any pastor, minister, or priest, to marry. Gather friends and family and have a ceremony; make it public. But, don't file with the government... they pretend to themselves that you're filing with them is a tacit acknowledgement of their superiority and their laws. One of those laws says that the "marriage" constitutes formation of a corporation, and that ALL product of this marriage-corporation belongs to them. This includes children. Court cases have been lost by parents suing schools' requirements because the state showed that the children actually belong to the state, and parents are just hired caregivers (hence the deduction per child on tax returns... that is your "pay", mom and dad.)