Justification for the mandate: Working women can spend up to $600 a year on contraceptives. These mandates will save them a nice chunk of money.
Why that's nonsense: Money is completely fungible and no other insurance was targeted.
Lots of people have $500 or higher deductibles on their auto collision insurance. Some don't cover their cars for collision at all*. A working woman who gets into a fender bender will spend money she had earmarked for diaphragms on replacing her bumper. If she doesn't have the extended warranty on her laptop and the thing dies, there's another drain on her contraceptives budget. How about insurance for her TV? The deductible on her renter's insurance?
$600 is a rounding error in health insurance where procedures you really want covered run into the tens of thousands of dollars. If you quizzed women across the country, I doubt they could tell you which $600 items were and were not covered in their existing insurance.
The selection of contraceptives was not random. It was done, as Tim pointed out, by Kathleen Sibelius, a (Vichy) Catholic. She knew what she was doing. She was trying to crush a rival to the State's supremacy in all things.
* - For example, my rust-eaten, 1984 Datsun pickup has no collision coverage.