Many people, including me, believe that having a single religous symbol in a Supreme Court building, to the exclusion of other symbols is creating the impression of establishment - which I believe is itself prohibited by the Constitution. I would not feel like I was in a neutral courtroom if there we a giant Quoran, or Torah, or 10 Commandments I passed on the way in. And yes, it is quite a different impression when there is a multitude of symbols/religions represented. It is the issue of having a single viewpoint that is the nexus to establishment.
Did you review Post #53, and do you claim that the Supreme Court was violating the Constitution in 1790 by displaying only a quote from Leviticus?
An impression of an establishment is not an establishment. It's not an establishment of a religion just because of how you feel about it. This is the same mistake the left always makes, they don't understand the difference between persuasion and coercion.
It's not a law, it's a monument. The federal court isn't demanding that an unconstitutional law be overturned, they are demanding that a government official cease expressing his religious beliefs, which is forbidden by the other clause in the first amendment (you know the one).