Other faiths (or non-faiths) displaying their message shouldn't detract from the one that another person likes. Why does the menorah not set the Christians into a lather? Oh...It's only beliefs that they do not like...
Tough... Last I heard this was protected under the First Amendment. You don't like it, don't look at it. You don't want it on public property, then keep it ALL off of public property... Wow... I just had a flash of deja-vu....