Judge issues order keeping Confederate memorial at Arlington Cemetery for now

[Igel]

9. Because the Executive only has authority as granted in the Constitution.

I don't see "park administration" among what's listed.

Everything else is law as established per our democracy by Congress.

Then again, perhaps this blip from the Great Wiki might provide some hint:

In 1901, Confederate soldiers buried at the Soldiers' Home and various locations within Arlington were reinterred in a Confederate section that was authorized by Congress in 1900. On June 4, 1914, the United Daughters of the Confederacy dedicated the Confederate Memorial designed by Moses Ezekiel. Upon his death in 1917, Ezekiel was buried at the base of the monument as he was a veteran of the Confederate army.[92] All Confederate headstones in this section are peaked rather than rounded.[93] The Naming Commission, appointed by Congress, has recommended removing the Confederate memorial down to its foundation.[94]

After all, the land purchase for Arlington was authorized by Congress.

BTW, the core of the cemetery was Robert E. Lee's estate.