AJ wrote:

Presently a mall security truck drove up and the guard told us to
disperse because we were breaking the law.

I think a stern letter to the mall would be in order. The guard has the
right to ask you to leave mall property, no more and no less.
Protecting a neighboring airport greatly exceeds what he was hired to
do. Threatening to call the police is highly questionable and
threatening people with his baton could land him in jail. You would
have been well within your rights to call the police and file a
complaint.