First,Venator,your avatar is great (hail Satan,as well as Mercyful Fate).

Secondly,about your question,I must say there is no such thing in my country (in out courtrooms/courthouses) that they display those 10 Commandments.But,if I would see such thing in the court,first I would find it funny (hey,it's like they are trying to say to the thief "don't steal",when it's in his nature,ha!),and also I would see it as a Christian propaganda (man,they put their nose everywhere,trying to get into every aspect of our lives,anyway they can).

For what I have read and understood from your post,it looks like the courts in America are "obsessed" with Christianity.