You have a really good point here Iz...yes...for the most part we still have the freedom of expression...but sadly...this now depends on what one is expressing.
For instance...public display of this painting is totally acceptable...as all the other art work depicting BHO as messiah...but somehow....public displays of Nativity Scenes (the birth of the true Messiah) or the Ten Commandments or anything even remotely Christian such as Christmas trees...not so much.
I didn't know that Union Square in NYC was private property....

Well...it certainly is very public private property to multitudes from not only the US...but travelers from all over the world....NYC is quite the international hub.