I sympathize with Christian parents who protest their kids learning about Islam in school, in a sense. It is natural to want to protect your children from ideas you deem dangerous and all parents do this in one form or another.
And it is some of these same feelings that make my wife and I insist on not sending our kids to public school. Except we’re not worried about our kids learning about Christianity, Judaism, Hinduism, etc. We’re worried about everything else that children are exposed to, i.e., the true religion of the modern liberal secular world that saturates the very air you breath.
That is the true danger posed to all those who believe in organized, traditional religion, Muslim and Christian alike. And even then, we do want our kids to learn about liberal secularism and other modern progressivist ideologies, but on our own terms, not in the highly biased, propagandistic environment of government facilitated institutionalized learning, where these ideologies are taken for granted.
In 10 to 20 years, when these Christian children grow up and abandon all vestiges of their faith because they find organized religion outdated, backwards, useless, etc., I hope these anti-Muslim Christians look back and realize their folly, distracted by Islam while, behind their backs, the fire of secular modernity consumed their families.