Microchipping is optional, and enters your dog on a global database should they ever be lost and turned into a shelter. Registering your dog with the city on the other hand is mandatory. The vast majority of dog owners do microchip their pets, but opt not to register with the city annually. Over the lifetime of a dog, licensing with the city costs well over 10 times more than microchipping, and offers far less benefit to the owner, if any at all assuming a dog is already microchipped.
As a dog owner myself, I seriously don't understand why some owners don't pick up after their pets. Even if the mess is ignored, many fatal diseases and harmful parasites are transmitted by feces, and can live in the soil for months. The group which suffers most from not picking up poop is the dogs themselves, not to mention the owners who rack up serious vet bills to treat their pets.
As for non dog owners, I, like most dog owners, make every effort to be courteous to them and hold my dog close on the leash. However, when they are rude to me just because I have brought a dog into their presence, they can expect to be seriously told off!