If you read up on the IeSF, it becomes much more clear what is going on.
-The IeSF is a South Korean organization; it is not Finnish. Ok, technically, it has a number of "member nations," but it is dominated by South Koreans. This tournament in Finland was a local qualifier for a larger international tournament. The local (Finnish) tournament organizers protested against the male-only rule, but couldn't convince the IeSF to relent until the media backlash started.
-The people who run the the IeSF aren't young male hormonal gamers. They are, by and large, middle-aged male executives at media and marketing companies. Their ultimate goal is to become the equivalent of the International Olympic Committee of e-sports, so that their companies can commercialize e-sports in the same way the Olympics were commercialized. However, they haven't been all that successful yet - they don't control any big-name tournaments in any of the games that I follow.
-As I mentioned already, the guys making the rules are older Koreans. I'll quote an interesting anecdote I saw on Ars Technica's comments:
Koreans can be remarkably thoughtlessly sexist (and racist, etc) without thinking about the broader implications. This is highly visible every time you park a car in a modern shopping center - there are reserved spots for women. The parking lanes (marked in pink) are wider and closer to the entrances. These aren't parking spots for expectant mothers or women with small children. These are parking spots for all women, with forethought that they're doing women a favor because they can't park cars as well as men. Westerners see this kind of thing and are instantly offended by the blatant sexism. A Korean will be confused as to why you don't see that women are obviously better off this way.