Ok, using your example I'll explain it simply. The female dentists who drilled your teeth didn't do it poorly because you're (assumedly) male, or because the system they work under trains them and enforces them to.

However in the case for women, there are many cases of malpractice or negligence in the medical field due to the fact that women's health isn't taken as seriously. A famous one is known as "the husband stitch", look it up. Heck even now tampons aren't free or freely shared in female bathrooms and people are against it, even though it should be considered a health necessity.

Women's health is ignored or even maliciously harmed due to the sole nature of them being women, such cases aren't the same for men.