Confused policy on contraceptives

The current political debate on whether Government health insurance should cover purchase of contraceptives by employees of Catholic institutions is a confused mess. Relying on first principles provides the answer. The purpose of insurance is to cover the risks of intentional, deliberate acts, not the acts themselves. We buy car insurance to cover the risks of accident, not to reimburse us for buying the car. Medical insurance generally covers the costs of pregnancy due to the risk of contraceptive failure, but there's no reason for it to cover the cost of buying the contraceptives themselves. Why should other people pay for one family's contraceptives?