Why did Anne act the way she did?

Anne tells the group that she intends on marrying Allan who is a "normal" person. Alan had previously turned Sophie in for her Offence. The group is angry saying that it is too dangerous for her to marry Alan. He might compromise the whole group should he find out. Anne argues that the numbers in their group work out that two girls will have no spouses. She argues that it is unfair for two girls to go without the happiness of marriage and family.