Compulsory education should not be a stalking ground for groomers.
Aw shit I gotta rant on this one..
A school's/teacher's job is to educate
A parent's job is to give food & shelter to the little mutha fuckas as well as the guidance they need to establish & strengthen agency.
The world is going to tell my children all sorts of shit (already has through school, friends, internet etc), I ain't worried about none of that cause I'm very confident that the tools I've given them will work & I'll support them in any choice they make for themselves; granted it's not against the law.
IMO there is one thing you should not do as a parent & teacher and that is to remove a child's agency. It's important to allow them to understand things on their own terms as best you can without installing yourself (don't know how else to say it). To avoid doing that as a teacher/school you need the parent's involvement, as you cannot do anything else as a school/teacher other than educate. If you attempt to educate without the parent's involvement you are inherently removing the child's agency as only a parent can provide the guidance they need (if the parent(s) are available and capable). Otherwise, you'll be changing that school/teacher-student relationship to something more complicated than you're equipped to handle. At that point, all the school can do is recommend third-party assistance. Why in the world would anybody find that more desirable than working with parents is beyond me.
This mom doesn't sound like she's upset about what was being taught, she was upset about not being informed and I'm am totally onboard with her ship setting sail up the ass of the school board.