> It’s also mighty interesting how it’s always the male division that’s open, until you happen to have a sport where women are beating men at it, and then suddenly it’s the women’s division that’s the open one!

Hypothetically you could have three divisions: open, men, and women. In many contexts it's more practical to have two, where one is open. In those cases, if the sex that didn't win more was also the open division, then people would complain because both divisions would be dominated by players of one sex.