This is what people believed back when it was first marketed to the public. It’s part of why it was so taboo, and it’s also why they introduced a placebo week, or a “mock” period. It’s because people were not welcoming to the idea of a drug that could stop all of that

Also, in many cultures, there is a lot of pseudo science or lore around periods, or this belief that periods release “toxins.” So to them, stopping your period could be seen as a bad thing

The reality is that all the pill is, is hormones. Your reproductive organs only produce an egg, or endometrial lining, or release the lining, in response to hormones. Birth control pills (monophasic pills, anyway) is just a combination of hormones that mimic a stage in your cycle where you won’t release an egg, won’t produce lining for a fertilized egg to stick to, cervical mucous won’t be welcoming to sperm. That’s all it’s doing, responding to hormones as it normally would