Because part of overcoming menstruation is to naturalize it. Even in 'first world' countries men believe that women 'suffer', that 'we suffer' from menstruation, and not that it is a period of lucidity, mental and sexual lucidity. And that contains stem cells.
Hiding it, omitting it or not mentioning it to children, using certain euphemisms have contributed to having a negative, "dirty" or disgusting view of it, to the degree of holding or excluding girls and women when they have it. There are cultures, in which it is even believed that the menstruating woman can sour the food if she touches it, prepares it or that she calls the bad omen if she touches the boats. So the degree of ignorance about menstruation.
Talking about it naturally, demystifying it, takes away its hermetic character. Talking about menstruation naturally is not only necessary, it is important. Our blood is clean, the only dirty blood is what men shed, in their wars.
And we will continue to do it, however 'obsessed' we may seem to you :)