You're missing the point. For younger children, it's not about being LGB now--it's about decades of replicated research showing that many gender-dysphoric younger kids grow up to be LGB adults if left alone.
We're talking past each other. You seem to think that if the guide contains no religious arguments, the fact that the FPA is the first org described (as a "Christian ministry that advances biblical citizenship") is irrelevant to a public school official. Let's agree to disagree.