Agreed - but not every dog on the Island responds to pssst or "no" or even sticks and rocks. There are dogs here (just like the states) that have been trained to fight and attack and then allowed to run free in public areas terrorizing humans and other animals.
2 neighborhood dogs had my cat trapped in the mangroves and had my dog not fought them off, she would have been mauled to death. They visit my yard several times a day now looking for my cat (who is primarily indoor, she just happened to follow me to the laundry). They are cat killers and had my friends cats trapped on their porch last week. This behavior is NOT OKAY and not the animal kingdom's way of working things out. If I could figure out who they belong to, I would file a police report.
Chances are, the owners have no idea what their beloved pets are up to all day. Now, is this responsible pet ownership? Me thinks not.