If you bled in random places every month on the outside of your body, people would understand why you where in agony. People would realise why you couldn’t go to work or school or why you couldn’t even get out of bed.
But, because people with endometriosis bleed on the inside, and it’s a long (probably latin) word that no one has really heard of, no one understands or gets it. The consequence is that women with endometriosis suffer massively. They often even encounter great difficulties to get a diagnosis and the treatment they need to manage their pain.