The safari at Six Flags in New Jersey is nuts. We too saw people feeding the animals anything and everything that they could find in their cars. The facility is very clear with stating that you cannot feed the animals, but people don't care. It is sad.
I tend to be optimistic about people, but I am now convinced that your average person has a set of rules that he or she professes to live by, and that same person has a very large "gray" area where he or she will bend those rules to a great degree. Unfortunately, when you bring a mass of humanity together at a place like Disney or Six Flags, you see more people dabbling in that "gray area" than normal.
A major reason (aside from concentration of people) that you see guests bending the rules at Disney is that people on a Disney vacation tend to feel that they "deserve" special treatment. Everyone's expectations for EVERYTHING are higher at Disney. There is a total feeling of entitlement. Most people go with the flow and do the right thing, but even if 1% do not, that is a LOT of people.