Per federal law, parents have the right to review, request amendment to, and release education records without restriction. Also by federal law, schools are required to maintain a child's privacy in regards to outside 3rd parties. In the event of needing to disclose info or release a child's education record, the school must first get informed consent FROM THE PARENTS. Not the child, who cannot do so, but from the parents. How is that possible if parents are left in the dark? The parents determine who beyond themselves and the school should have access to the child's information but now you have activists wanting parents relegated to on a need to know basis. It is the parents who are ultimately held responsible for the child, are these teachers going to assume those obligations? No. The overwhelming majority of parents are not abusive so wanting policy to deny parents information about their children and issues related to their well being because a small percentage "might" be abusive is not in the best interest of children or of families overall.
Activists want it both ways. If parents want to (approve the) transition of their child, they scream "Don't interfere!". "Don't usurp parents' rights, they know their kids better than anyone else and if they say their kid is trans then they're trans!!" Only then do activists support parental rights. And don't dare suggest the child may not be trans, don't suggest other mental health issues be tested for and ruled out, or that the kid may simply be gay or, here's a novel thought, simply going through a phase as all children do many times over while growing up.
Yet, parents who don't agree or simply doubt their kids are actually trans should be stripped of those same parental rights. Now they should be left in the dark with others who are not the child's guardians deciding what's to be. Even though it's the parents who will be held legally, financially, and emotionally responsible for covering anything related to those decisions...and left to endure any fallout. "Parents know their kids better than anyone else"... seems that's only if they're on board with a school's or activists' agenda.
Educators are not always right, they are equally flawed with their own biases as any parent may be accused of. They also don't necessarily know more or better, many parents have equal or greater education and discernment. Not telling parents what is going on with their kids is potentially harmful to the child. It's arrogance and bias, and entirely one-sided. Children are notorious for being imaginative at best and flat out liars at worse, their logic is not adult logic. Add in some other mental health problem and it's a mess waiting to happen. So yes, schools are obligated to inform parents of their child's feelings and behavior as there can be more and other going on than what the school was told by the child.
Transgender, especially medical transitioning, is adult space. Period. A tiny, less than 1% of the population has gender dysphoria and of that segment, only a fraction are minors exhibiting early dysphoria. Not all parents who don't agree with transitioning a child are phobic. There can be more and other going on than what the teachers think they're aware of. Frankly, much of this smacks of homophobia. "Oh, you're a boy who likes girl things or vice-versa? You're trans!" Uhm, no. Most of the time a gay child is a gay child, abd and transitioning is not required now or later.