To answer your question. In medicine and biology is a concept called homeostasis. Homeostasis is the tendency of an organism to maintain its normal functioning. Health insurers have traditionally paid for claims for people to return to homeostasis. So for women homeostasis means that they have menses and ovulation. This is why insurers never paid for birth control, it is designed to interrupt the normal functioning of a woman's body. Now if a woman had a reason she couldn't menstruate an insurer would pay claims for her to try to correct that.
For a normal functioning male achieving an erection is also normal. For a male to be unable to achieve one is considered a medical condition. So insurers traditionally paid for claims for corrections for erectile dysfunction. To pay for tampons or pads - you could make an equivalent argument that insurers should pay for toilet paper.