Its a good question. Imagine if the situation were slightly different. Imagine if, like porn, this site became mainstream. Then, if a girl would want to learn about CS this would be the place to go. Consequently, she would be subject to all of the objectification of women that this site puts forth. That is definitely a bad thing.

If there were a competitor which didnt have that aspect and people were split: men would go to this one and girls to the other, it creates a division between the genders. The situation then would be eerily similar to the idea of "separate but equal" and we all know how poorly that turned out in the past.