Maybe the law should read that only local groups can put up monuments. That way, they represent the community, not some politically-correctness thing. The Satanist group is from New York - they shouldn't have any sayso as to what happens in Oklahoma. Now, if they have a branch in Tulsa, and the branch wants to put up a monument, that is different.
Problem is, when you let outside groups dictate what can or cannot be put up, then no one is going to be happy. I could go around the country demanding that all government and public education places that have statues or names of Chris Columbus on them change because I am offended that some idiot who doesn't even understand the science of his own time and then goes and starts slave trade, paprticipates in human trafficing of children, did horrible acts against humanity and was actually stripped of his office and title by his own government for these reasons. I could sue the entire city of Columbus, Ohio, sue the District of Columbia, sue CBS, etc.
Let's stick though with seperation of Church and State. Does anyone know what the First Ammendment actually says?
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances
This speaks to the United States Congress and the federal government. The issue in place is about an Oklahoma State Building on state land. First Ammendment doesn't apply (although some Supreme Court decisions may state otherwise - I honestly do not know every court decision ever made, I am not a law student). By extension, the first Ammendment does not apply to schools or city governments.
However, in 1947, there was a Supreme Court decision. Justice Hugo Black wrote, 'The "establishment of religion" clause of the First Amendment means at least this: Neither a state nor the Federal Government can set up a church. Neither can pass laws which aid one religion, aid all religions, or prefer one religion to another ... in the words of Jefferson, the [First Amendment] clause against establishment of religion by law was intended to erect 'a wall of separation between church and State' ... That wall must be kept high and impregnable. We could not approve the slightest breach."'
This did extend the first Ammendment to include states, and, from my brief research, is where the term "seperation of church and state" appear.
So governments cannot establish a church, and by this ammendment, a state or federal government cannot setup their own religious monuments (this does not apply to cities). But, likewise they cannot prevent a private entity from setting up a monument because to do so would show preference to one religion or another (or lack of religion). So they cannot stop a group from doing this.....
EXCEPT.....
and it doesn't say this, but you could go back to this - this is STATE land, so a New York group really should have no say. If it was federal land, that would be different.