"This would IMHO be difficult to do in the U.S. for private or religious schools, given the constitutional freedom of speech and religious freedom issues."
This is something I find difficult to understand - due, no doubt, to my imperfect understanding of the US constitution. I understand the right to 'free speech' and I think I have knowledge of the historical 'separation of Church and State'. But I thought that the latter meant that anyone can practice any religion they want but that governmental obligations were or should be entirely a-religious.
If the education of children is a government requirement (federal and/or state) in whatever form it takes (including 'home-schooling') doesn't that mean that the curriculum should be a-religious to comply with the constitution? Even if other, additional, 'religious' schooling is permissible as an 'extra'?
Does the constitution also guarantee a freedom FROM religion of whatever brand?