My DCs former school had a bunch of women from a certain group decide to picket outside the school gate.
They had taken offence to the school teaching about sex, LGBTQ and about pregnancy. They also found it offensive that the teens were taught that not everyone is married when they have children. All standard national curriculum stuff.
They stood outside with banners, screaming at people. My DD had one scream at her, in her face, because DD had a range of badges on her blazer, including at the time Black Lives Matter emblems, and Pride rainbows. DD, being made of sterner stuff, told them to get out of her way, as being near may mean they "caught homosexuality" as she is gay. They were very angry and she walked into school, laughing. Other kids didn't find it hilarious though and a few were very upset.
At the end of her tether, and with no help from the police, the headmistress made a note of whose parents were at the gate. At the end of the school day, each parent was emailed. In the email, it said "our school is inclusive and as such, we teach National curriculum items on Sex, religion, marriage, pregnancy and many other topics to help our pupils grow and make informed choices. Should this be something you no longer wish your child to engage in, we advise you to give us notice that your child/ren will be deregistered by the end of the week. Otherwise, your picket is expected to cease by tomorrow at Registration or those pupils will be taken off the roll."
It then went on to add the current figures for waiting lists for other schools in the area. The rest of us received an email detailing the above and welcoming in school discussion but not abuse of pupils and staff. It also said if anyone else wants to dereg, let her know.
The next morning, not one of them stood outside and DD said only one boy from her classes disappeared.
I felt this was the best way to deal with morons trying to change how we do things. Never apologise. Never give in. All schools should do the same.