Fatty Arbuckle had a very intelligent dog that appeared in his movies that was at least part pit pull. Quite a lot of indiscriminate breeding of those dogs have gone on since then. These dogs are frequently owned by white trash/gang bangers/Illegals/meth heads who are likely as poorly bred as their dogs. Some of these pit bull breeds may even be bred with other bully dog breeds so that they become even more aggressive. These dogs are IMO simply more than most owners can control. Cesar Milan may be able to handle them. Most people do a poor job of handling dogs at all. If they do a poor job with a pit bull, it can be fatal.
You have just described some residents of a nearby tourist area...