Actually, a school board does not have the right to impose religious doctrine on school curriculum, even though the board members, as individuals, have the right to write and publish editorials opposing this restriction.
(2) From a strictly survival viewpoint a school board has a natural law duty to inculcate some basic, keystone, fundamental religious ethics, morals and understandings in its students, without which many students are unable to learn to make their way safely in society and live. And many classrooms are bedlam-esque child-care facilities without ANY appreciable learning.
Without which such training look what is happening, my friend!
What is the rate of births out of wedlock? Such children are troubled all their lives for lack of a parent, and most by far for lack of a solid good father.
This bedlam in what should be a tranquil learning environment is a direct result, imho, of the religion of secularism which includes designer-less evolution. Education has devolved.
(3) Our nation's founders for generations were themselves taught in schools where "religion" was a core part of the curriculum. Such an education ELEVATED them, and their whole generation. Woe to us, under the foolishness of secularism.
A school board, as an agent of the state, has the right to decide whatr the contents of a school curriculum shall be. The notion that one can separate morals from religious sanctions is a recent development. It is the right of the state completely to secularize the curriculum, but this is easier said than done, because there is a tendency to introduce elements of an ideology that may be hostile or disparaging of religion. Religious neutrality is the goal, but that means fairness to both religion and irreligion. In practice, it often means unfairness to believers. For instance, an anthology of English literature of the 17th Century would, to be representative, have a high religious content. Not to include this content would be to present a false impression of that literature. Since any system tends to justify itself, testing would then include only questions of the secular content, giving the impression that only such knowledge is important, that an educated person can afford to be ignorant of it. So knowledge of Donne’s poetry—not a good example—passes out of the public view and becomes esoteric. How quickly the content of a common education can change can be seen in a more trivial example, how students are no longer familiar with fairy tales.