"No solicitation on premises without written permission of management." It is there so the Mall management can dictate what messages can be seen there. Now I think that if I ran that mall that guard would not be working there anymore. There is also a sign on the local malls around here in Florida "If you are asked to leave by an employee and you refuse we will press tresspassing charges" Here it has to do with spring breakers but the concept is the same. A mall employee asked him not to display that message in the mall or leave. Yes it was stupid. Yes I bet the guard wished he had kept his mouth shut. He still was within his rights to have the cops eject him.
Others brought up the color issue. Yes you can eject a black person from private property. If the reason you ejected them was solely based on color you can sue in civil court for damages. You can go to the Feds and file a complaint so they would look into a criminal charge, either way you are no longer on that property as of that moment. You will be forced to go away and deal with it later.
thanx,
bill