We cannot allow one religious viewpoint versus another viewpoint. Banners containing religious icons would be definitely troubling. That is why when the holiday banners were produced three years ago, we could not choose a graphic with a Christmas tree - because it had its roots in Christianity. The City has been sued several times regarding perceived religious endorsements, so if you can avoid any display of religious icons, it would potentially avoid a lot of future trouble. 187 is a very emotional subject.
English language is the official language.
There is nothing wrong with English on a banner as long as the words are not offensive. Graphic art is one thing. But when you start puffing up political messages, then it becomes problematic. There is nothing wrong with promoting harmony - and the word message is obviously promoting diversity and harmony. However, when we start conveying messages on City lamp-poles, then we open R up and conceivably the City could be forced to put up messages counter to this message of harmony.