Feminists

and there also isn't sufficient evidence to preclude it because there hasn't been any controlled experiment to assess the risk with grizzly bears. The polar bear study indicates some attraction, the black bear study revealed none.

As you noted, the incidence of bear attacks is pretty low. IMHO the NPS issued the warnings because people expect them to offer advice on the topic.

A lot of health & beauty products smell like food to critters and that's why the standard advice is to avoid using them. It's a relatively low risk and easily avoided by using unscented products and putting these products in the bear box or hanging them with the food.

The menstrual blood thing really is out of proportion to the risk though and it's good that NPS has tried to address it.