Although the ten commandments are strong moral guidelines for people of all religions to follow, and do not differ widely from the moral viewpoint of most world religions, it is still a Christian tradition and should not be allowed to be display publicly in federal buildings because it violates the separation of church and state.
The United States of America has been founded on the idea of separation of church and state. As colonists were settling America on the east coast, they were escaping religious persecution from Europe. To invalidate a founding principle of the United States and declare it wrong is a huge step and should not be taken in the United States.
I think everyone is entitled to their own opinion, and entitled to their own press of that opinion. They can publish it wherever they want if they own the building. If you do not like the sight of it, simply do not look towards it. It is the same as if there were puke on the floor.
I do not feel it is wrong to display the Ten Commandments in public buildings, as long as they are not to be interpreted as the ultimate law. If the Ten Commandments are a part of a mural, decoration, or other iconography, mixed with other sources of historical law, then they are acceptable. After all, this is America and we value free speech. However, if a courthouse has the Ten Commandments inscribed in the wall behind a judge, then it would seem to alter the purpose of the public building.