The MAIN reason Breed-specific legislation exists is to impose a sort of 'second level' housing discrimination policy on folks whom the good (white) burghers regard as "undesireables."
There's more, of course, but that's the main one:
Breed-discriminatory legislation (BDL) refers to laws that target dogs based on how they look rather than their actions. Hundreds of U.S. cities have already enacted BDL, and more cities adopt it every year. Many cities and counties—plus Marine Corps and Army bases—have banned select breeds altogether. Other cities enact BDL that automatically labels dogs of certain breeds as “vicious” or “dangerous” regardless of their behavior. These laws may require owners of the targeted breeds to follow strict guidelines, such as sterilization, proof of liability insurance, housing of the dog in a cage with a roof and floor, and muzzling the dog when on a leash. Currently, BDL most often focuses on pit bull types (dogs that have “pit bull characteristics”), but some cities also target Rottweilers, German Shepherds, Doberman Pinchers, American Bull Dogs, Bull Terriers, Mastiffs, Dalmatians, Chow Chows, other large breeds and mixes of the targeted breeds. Here, we outline the inherent flaws of BDL, why it doesn’t work and why it concerns every dog lover.