I think it's more anti-sisterhood to dismiss somebody's pain just because it's originating from their uterus, so cannot possibly be as bad as they think and even if it is, tough shit, stop whining and get on with your housework/chores like a normal little fembot.
I've run the First Aid/Medical room in a school. Some girls would occasionally come along if they were having a particularly painful period, if they needed some spare clothing, some you'd never see unless they needed an extra pad and some would look grey, some would throw up or faint, plenty had period shits (diarrhoea and bowel pain), some had the sharp pain nicknamed javelin arse (there's a version that goes straight up the pubis, too), some were later diagnosed with endometriosis and/or severe anaemia and some had full blown contractions and would pass decidual casts before falling asleep from exhaustion. And some would decide that if this is just all part of being a woman that they weren't having anything to do with the entire business (yes, often Autistic) and they would do anything to stop this continuing for the next 40 years.
The one thing that stood out was that being caring towards them made them feel better. For some it was being sympathetic and encouraging them to move around (and go back to class), others needed a calm person to fetch them emergency clothing, some needed an independent adult to call home to let them know that this was not a normal level of pain and a GP appointment would be a good idea and some needed twenty minutes to curl up with a hot water bottle to get over the sharpest pains before returning to class for the rest of the day. Oh, and somebody to supervise them taking their painkillers to make sure that they didn't accidentally overdose by taking more over the course of a day.
Nobody's period ever became pleasant or inconsequential as a result of another woman telling them one way or another tough luck, this is your life as long as you have a uterus, you're letting The Side Down. And it makes me sad to think of the thousands of girls I saw, for some of them, I could have been the only woman who had spoken to them kindly about it.