Of course banning guns, whether it is done by the government or by private individuals on private property, is complete total idiocy since it does not make anyone "safe" but only makes some folks "feel safe" while adding to some politician's power. Actually an argument can be made that gun free zones make people in those zones "unsafe" because basically, to a criminal, those gun free zones are nothing more than target rich areas free from any resistance.
Thing is.. even if it is idiocy the private property owner still has the right to be an idiot and has the right to ban guns.
And personally I do not think banning guns is wise... but I still respect the right of a private property owner to unwisely ban guns.