I am no convinced that schools have any business teaching kids about sexual ethics as such, what sexuality means or is for, who it is right or wrong to have sex with (beyond legal stuff etc) or what marriage is meant to be about, or any of these kinds of topics
Goosefoot, I appreciate what you're saying about schools moralising about sex and relationships, and accept that it's inevitable that, if schools are teaching about sex, some lifestyles/beliefs will be given more airtime (sometimes deliberately and sometimes unconsciously, perhaps because people sometimes forget that not everyone is like their circle or because there's insufficient time to be inclusive of all of them).
And I agree that schools shouldn't be taking a moral stance on legal activities. I wouldn't expect any schools except faith schools to be teaching that sex should only take place within a marriage, for example.
But we shouldn't throw the baby out with the bath water on women's rights.
I think it's absolutely imperative that schools take responsibility for teaching pupils some important aspects of sexual ethics, such as consent and the differences between respectful and abusive behaviour in relationships. For many young people, school will be the only place they can pick up these messages, and I think it's absolutely vital that they're discussed. Similar to vaccinations typically being done in school to reach as many children as possible.
Even outside of sexual ethics, homosexuality should be coming up in the context of sexual health (contraception, etc) too. It's important for schools to acknowledge that many people aren't having heterosexual sex and that this isn't the only possible or acceptable option.
There are several issues with not acknowledging homosexual sex when teaching sex education, including the fact that many pupils might not appreciate that safe sex is still an important consideration between two partners of the same sex (I know I didn't!). Depending on their background, a heteronormative approach to sexual education might also trigger feelings of shame and isolation about a pupil's own sexuality, since in that context, it appears to diverge so far from the expected norm that it's not even been mentioned as a possibility.
IMO, challenging gender ideology in schools and elsewhere is essential. But scrapping sex education altogether in schools isn't the way to achieve this and will also have unintended but devastating consequences for a great many young people, and especially women and girls.
I don't think the religious/moralistic stance is relevant when considering gender ideology anyway, because no-one who believes in gender ideology regards it as a moral/philosophical belief (yet!). It's not an opinion to them, it's a fact.
People know they're not allowed to take religious/philosophical stances in certain circumstances. But having that kind of rule for schools wouldn't prevent them from teaching gender ideology as a fact, because they believe it is a fact and not a matter of belief. On gender, they're not saying 'you should believe this' because they believe it's the most morally-worthy position to take, they're saying 'you should believe this' because they believe (or want to be seen to believe) that it's an indisputable fact.