So bar those two women from the PTA or whatever. A penalty is being imposed on the CHILD, what did the CHILD do to deserve it?
The child probably didn't do anything. She was being cynically used by those two women in an effort to desensitive other people's children to the idea of same-sex "parents."
The girl either had to be prevented from ever mentioning her mother's living arrangement, or the other kids would be introduced to the idea in a way that would make them sympathetic to it -- i.e., if their friend if from a household like that, it can't be so bad.
It isn't a fair situation, but it wasn't created by the Christian school. The sins of the parents are always on the heads of the children. It's a shame, and the child never does anything to deserve it, but it doesn't mean that others have to abandon all standards to prevent it.
You also have to wonder how this whole thing came about. I get the very definite sense that something important is being left out of the story. The child had been admitted to the school, right? Nobody knew about her mother's living arrangement. She was expelled when was "reprimanded for talking to the crowd during a football game." Talking about what? That it's possible to have two moms? That her mother's living arrangement was just as good as having married, heterosexual parents? Maybe she was deliberately proselytizing.'
I'm not saying even that would be the girl's fault. She wouldn't know any better. She has a mother who has taught her perversion.
In any event her presence at the school could only help the gay agenda, and hurt the efforts of the other parents to teach their children that some actions are simply unacceptable.