I don't have a problem with the Ten Commandments monument, and I don't think it's unconstitutional, but I don't think your argument will fly...
If another judge wanted to put up a Wiccan or Buddhist or Hindu monument next to Judge Moore's monument (which is on public property, not the Judge's personal property), would you say the other Judge had a right to free exercise of his religion as well?
Yes. Would the ACLU?
I suspect the Liberal Judge Myron Thompson would rule that it was OK.