Christian agenda = Teaching kids "God exists"
Atheist agenda = Teaching kids "God does not exist"
Neutral agenda = Teaching kids "All the words except GOD"
The "atheist agenda," which really should be called the secularist agenda, since there is room for Christians who also support church-state separation, is to get to where the Australians, for example, are now, and quit having to think about religion at all.
Atheists, or more properly, anti-theists, push back at creeping theocracy where necessary, and are thereafter pretty indifferent about religion, which is why the American atheist's experience is so different from the Australian atheist's experience. From what I read from the Australians, the Australian church has little impact on anybody that doesn't want it to.
American atheists have to deal with an organized, politicized form of Christianity that would remove their rights to same sex marriage and abortion if could, and impose religious values on the nation using the force of government to carryout the will of the church.
Heaven forbid that someone might suggest the possibility that there is a God.
In public schools? That is where the mention of God from the Christian perspective is pretty much off limits.
I would suggest that the parents of children that want them raised Christian would be very unhappy if that discussion were permitted in the public schools. There are far too many teachers that would teach critical thinking rather than what is being called brainwashing in this thread (I'd say that indoctrination is a better term, brainwashing implying more severe forms of indoctrination such as Stockholm Syndrome, cultish behavior like the Branch Davidians, Manchurian Candidate scenarios, and the like).
If I were your child's teacher, when we got to discussing God, I would introduce her to rational skepticism, or the idea to not believe without sufficient cause. We would also discuss what faith is, and how it varies from reason.
Then I would ask what her reasons for believing in God were, and examine if they were sufficient. I wouldn't say that there are no gods, just to examine why she believes or doesn't believe in them.
This is the essential difference between indoctrination and teaching academic style. With the latter, the teacher doesn't really care what you believe, just what you have ;learned, even if you don't believe it. In a class on evolution, nobody is going to ask you if you believe the theory, just whether you can recite its principles, how it came to exist, and what evidence supports it, and the like.
In Sunday school, evidence isn't offered, just conclusions to be accepted on faith and authority, repeated until the child repeats them back, with great interest in whether these ideas are believed or not, the purpose of indoctrination being to make them be believed.
I would likely also teach her that.
You might be good with that. It might even be what you teach or taught your children as well.
But many parents would become incensed, and yank their children out of such schools to put them in religious schools or home schooling.
We're past the days of the Scopes trial when every teacher except Scopes could be expected to indoctrinate children in religious belief, and he could be stopped for not complying. Today's public school teachers are different.