The IeSF explained in an official announcement:
On 2nd of July, 2014, the IeSF’s policy about gender division, which separates the female division and the male division, has been brought into question. The IeSF has listened to the gaming community and has carefully considered their opinions. Upon hearing these concerns, the IeSF convoked an emergency session of the IeSF Board to respond.
As a result, IeSF shall have two event categories: “Open for All” events and events that are reserved for women. The events which were initially set aside as the male division will now be open to all genders, and the events which were initially set as the female division will remain as they were.
[Original] The International e-Sports Federation of South Korea typically splits genders up for competitions in games ranging from Starcraft II to Ultra Street Fighter IV, but in this year's tournament women will only be allowed to participate in two games:
StarCraft II and Tekken Tag Tournament 2.
While men can compete in Dota 2, StarCraft II, Hearthstone: Heroes of Warcraft, and Ultra Street Fighter IV, women can only compete against other women in the two games above. The conflict came to light when Redditor Karuta shared an e-mail stating that a qualifying round was only open to men.
An organizer explained the ruling as "In accordance with the International e-Sports Federation's tournament regulations, since the main tournament event is open to male players only. This is to avoid possible conflicts (e.g. a female player elminating a male player during R08) among other things."
Yes, because you wouldn't want the more capable female gamer moving on in the tournament over a less-worthy male opponent. That's only a conflict for male gamers, but it seems plenty fair to proceed that way for females, right?
A posting on the International e-Sports Federation's Facebook page states:
Let me elaborate a bit on the decision to create both male and female competitions. This decision serves two main goals of the IeSF:
1 – promoting female players. We know that e-Sports is largely dominated by male players and females players are actually a portion of the overall player base. By hosting a female-only competition, we strive to promote female gaming on a global scale.
2 – International standards. IeSF is very close to get e-Sports recognized as a true sports like it should be. Part of that efforts is to comply with the international sports regulations. For example, chess is also divided into male / female leagues.
But, we want you to know that we listen to you, and appreciate your feedback! Our efforts does not clash with the community opinion – but on the contrary – we are here for the future of e-Sports and will do our best to promote it as best as we can.
I can understand separate-but-equal genders in physical sports like basketball or baseball or tennis or whatever. Men and women have bodies constructed differently with differing musculature for different purposes, but in video games it seems like we're all on equal footing.
Wouldn't a world-dominating victory feel a little hollow at the top of popular competitive games if you knew there was someone of the opposite gender you never even faced off against?