I think that maybe the U.S. Supreme Court on Feb 29,1892 says and explains it the best.
Holy Trinity Church vs U.S.
The free, equal, and undisturbed enjoyment of religious opinion, whatever it may be, and free and decent discussions on any religious [143 U.S. 457, 471] subject, is granted and secured; but to revile, with malicious and blasphemous contempt, the religion professed by almost the whole community is an abuse of that right.
If we pass beyond these matters to a view of American life, as expressed by its laws, its business, its customs, and its society, we find everywhere a clear recognition of the same truth. Among other matters note the following: The form of oath universally prevailing, concluding with an appeal to the Almighty; the custom of opening sessions of all deliberative bodies and most conventions with prayer; the prefatory words of all wills, "In the name of God, amen;" the laws respecting the observance of the Sabbath, with the general cessation of all secular business, and the closing of courts, legislatures, and other similar public assemblies on that day; the churches and church organizations which abound in every city, town, and hamlet; the multitude of charitable organizations existing everywhere under Christian auspices; the gigantic missionary associations, with general support, and aiming to establish Christian missions in every quarter of the globe. These and many other matters which might be noticed, add a volume of unofficial declarations to the mass of organic utterances that
this is a Christian nation. In the face of all these, shall it be believed that a congress of the United States intended to make it a misdemeanor for a church of this country to contract for the services of a Christian minister residing in another nation?
Here is a link to the whole document.
Holy Trinity Church v. U.S. (1892)
One person who wants a non denominational prayer removed from the school wall over the vast majority is tyranny.
She is prohibiting the free exercise of religion.
It is a clear violation of the 1st Amendment.
We have non denominational Chaplains in our government and should be able to have nondenominational prayer in the school.