Dealing with an Anti-Feminist Community/Culture

While not a permanent resident of the community, my girlfriend is a member of a local Native American tribe, which most outsiders would not realize is very anti-feminist in their tradition practices. Probably the most disgraceful example would be their view of menstruation. Basically, if a woman happens to be on her period during a tribal event, she is banned from attending it (not permanently, just while menstruating). Their word for menstruation translates to "bad way." They used to even have small, separate houses for women to eat in by themselves, away from their family, every time they're menstruating because they would taint the pot of food that everyone dishes from. They must have come to realize over time just how incredibly stupid this is because they don't take it that far anymore.

Nonetheless, when her father died a few years ago, they held what is called an adoption ceremony in his honor. Preparations were made in advance and she was to play a central role in it, but since she was on her period the day of, she no-showed. She also put lots of work into harvesting and preparing Indian corn for a ceremony, but the corn couldn't be used on the grounds that she was experiencing what intelligent, rational people of the 21st Century would describe as the healthy, normal biological function of menstruation. We used it to make a stew.

The tribe's culture in general very much segregates women and men, with only men serving on the tribal counsel and other duties. Their traditional dance events also paint a picture of men as flamboyant and boastful while women are to be solemn, modest, and almost submissive in nature.

My partner considers herself a progressive, hippie/punk feminist, reading Bitch magazine and various pro-feminist blogs. Sometimes she preaches to me about womanhood, which is redundant since I virtually always agree. Yet these beliefs shut down in favor of obedience when faced by her tribe. For her to passively adhere to their barbaric practices frustrates me greatly, especially in dealing with an issue has sensitive as her father's death. I may come off as harsh, but if she has true feminist convictions, why let her tribe's behavior towards her body be the exception in a world of misogyny and unfairness?

Maybe she's just not bold enough to take at least some type of stand against these backwards practices. I sure would if I were in her shoes. Or, hell, maybe it's because she has the perks of a tax-free house, a massive trust fund for her son, and a large, monthly casino check. I'm not really sure... Your thoughts?