Is Football field is for unleashing dogs?

One sunny morning me and my two kids went to play soccer on a Catholic School football field. A few moment later a dog owner came in and unleashed her dog on the field. And a few minutes later, another irresponsible dog owner unleashed her 2 dogs to the feild. On the gate of the field clearly says ‘No Dogs Allowed’. I filmed the dogs playing on the field and the other woman approached me and says filming her dogs is harassment. I just told her “you guys are not supposed to unleash dogs in public area. There’s a place for dogs and for kids to play”. She answered to me, “you’re not supposed to be here as well because it’s school property”. It was supposed to be a nice day! Do you think it’s fair? Here in Toronto, there’s a lot of irresponsible dog owners.