It seems a little unreasonable to insist on a way of thinking about Constitutional law that has been moribund since John Jay's term and this role of the Court's fits fairly well into the common-law framework we've inherited from England.

It also doesn't seem clear to me how setting up a curriculum (a legal act, after all) can't be covered by that text, unless you want to go back and argue it is only concerned with preventing a church becoming literally "established" like the Anglican Church is in England.