Funny you should mention that - he refused that one too.
Does he have to accept every request for a display that someone wants to put up, no matter how irrelevant it is to the historical foundation of the country's laws?
Alas, we've wandered into hypothetical-land now. When his avowed intention is to celebrate his religious beliefs about what he sees as the moral foundation of the law, there's really no need to discuss things like the historical foundation of the law. Nevertheless, if he had wanted a display about the historical foundation of the law, he could easily do what has been done at the Supreme Court building, and display a variety of lawgivers from the ages, both secular and religious.
And that's supposed to be some kind of effective counterpoint? Whenever you lay down a principle, you should be expected to be able to apply that principle to different situations. Otherwise, it ain't much of a principle, now is it? Would you care now to answer my questions?