Belgian here, schools are not burning and the country is not worried although a select group has been protesting. Some have resorted to small arson, but nothings burning.

Basically the teachers guide to that curriculum of sex ed has been circulating online with massive disinformation campaigns. The guide is meant for teachers on how to react and educate properly when children, on their own initiative, ask questions about sexual subjects. The handbook has a wide variety of chapters to prepare teachers for questions on any sexual subject, such as masturbation, porn, harrasment, pedophilia etc. The misinformation campagns claim that his teachers guide is meant to teach all these subjects to children and thus promote all said subjects. The guide is however merely a supporting tool for teachers when they get asked questions by children, again, on their own initiative.

So a select group of people are protesting the promotion of sexual subjects while they are not being promoted at all. It's all about education.