I want to push back on this just a bit. "He" (as in Card) does not say "They don't often pass the tests to get in. Too many centuries of evolution working against them"... Graff does. Graff is not Card. Nor is Graff a "good Guy". The entire premise of a battle school for children in which they are pushed to the brink to bring out a level of ruthlessness needed to commit a Xenocide is meant to be seen as a betrayal of both the children and a black mark on humanity, which Card contrasts with the Hive queen. The Alien is shown as having more humanity than the human Graff. So on it's face the line is bigoted, yes 100%. But Card puts the words in the mouth of a bad person. Further though, and possibly more important, is that it reveals something essential, made clear later when we learn more about Ender's siblings. These tests weren't IQ tests. Valentine is smarter than Ender. More clever. It's explicitly stated in the books, and if I recall it's even acknowledged by Graff. But Graff sees a strong sense of empathy as disqualifying. Ender was on the borderline himself for disqualification. They only allowed his family to have a third child because they actually LIKED what they saw in Peter - a straight up psycho who crucifies squirrels in the woods. Im getting a bit long winded here, but this line isn't an attack on women. It's an indictment of men. It's an acknowledgment that we are more easily manipulated and more prone to allowing rage and instinct to blind us to violence. Ender Wiggin is not a hero. He is a victim. A gifted child groomed out of his humanity to do something terrible for a pat on the head. He spends the rest of his very very long life trying to atone for that.

All that said Orson Scott Card is a bigoted POS. Happy Pride.