LOS ANGELES -- Among dog lovers, mail carriers are in the best-of-breed ranks. Some 130 of them marched and rallied here recently to tell the public that they love dogs -- on leashes, behind doors and fences and out of sight. In this summer of pit bulls when dog-bites-man stories received some play, the mail carriers of Los Angeles are saying what all postal workers and emergency-room physicians know: dog attacks are a major public-health hazard.

During the dog days of August, when the Los Angeles march occurred, it was reported that 93 mail persons in the city had been bitten this year. This is 24 percent higher than the first eight months of 1986. The cost is more than $200,000 in medical expenses and lost time -- about $2,150 a bite. In 1985, according to the U.S. Postal Service, more than 5,000 mail carriers were bitten.

The predation is not limited to those making their appointed and often bloody rounds. More than 1 million bites are reported annually. The Humane Society believes that ''between two to 40 times that number of bites may go unreported. . . . We can conservatively estimate that in a typical year at least one in every 50 Americans is bitten by a dog.'' For the past decade, the rate of death by dog has averaged one person a month.

Behind the killing and maiming is a canine mania that allows the antisocial excesses, whims and lunacies of dog owners to go nearly uncontrolled by law and uncensured by public opinion. Whether pets are killers, biters or merely the average civic irk that keeps neighbors awake by barking and sidewalks and playgrounds filthy by defecation, dogolatry is at work.

The worship is sustained by an array of liturgists who profit: dog-food manufacturers, breeders, kennel and boarding operators, pet accessory companies, advertisers, vets, professional dog walkers, dog morticians, dog beauticians. Sales of dog food reached a financial high in 1985: $3.1 billion, up from $2.6 billion in 1980. Excluding vet fees, the yearly minimum costs of ownership are as high as $500 a year for a large dog.

The extravagance of dog owning raises ethical questions that are as rarely faced as the legal ones. A $500 tab is a sum higher than the annual per-capita incomes of the 55 poorest nations that have more than one-fifth the global population. Is it morally right for the 50 million domesticated dogs of America to be better fed, housed and medically cared for than 1 billion human beings?

Those who pose such questions risk being called cranks or, worse, dog haters. In ''Man's Best Fiend,'' one of the few books ever to offer candor on canines, Raymond Hull writes of the dog conspiracy: ''Read your daily newspaper, read all the magazines you subscribe to, and all the books on your shelves; see all the movies showing in your hometown; watch all the television programs you can receive. Chances are that you will see or hear nothing that is the least bit discreditable to the dog. . . . Thanks to the canophile, the dog is still sacrosanct, and woe betide the man who dares to jog its halo.''

The negative publicity given to pit bulls is likely to be temporary. The ''rare irresponsible owner'' argument is already appearing: it's only a few crazies causing the uproar, not the nearly universal law-obeying owners who control their dogs, praise motherhood and eat apple pie.

Tell it to the mail carriers. The Los Angeles Times quoted one 21-year veteran who lost a year's work following a biting by two Pekingese dogs: ''There's enough hazard on the street as it is without having to go into a yard and be attacked by a dog. It's insane.''

He's right. But where is the breakdown in mental health? It's among the owners, for sure, ranging from those who put themselves in states of mild to severe servility to walk or feed their pets, to those who turn their homes -- living room, bedroom, kitchen -- into dog runs. The larger mental aberration belongs to those public officials who know but don't act on the facts of the dog menace -- the 1 million to 40 million bites a year, the $500 million (1974 figure) for controlling, impounding and killing unwanted animals, the 3,500 tons of feces and 36 million liters of urine excreted daily, the decimation of horses and whales for dog food.

Unlike the clean city of Reykjavik, Iceland, no big city has ever had a mayor with the bravery to call for a banning of dogs. Doglessness is well justified for health, safety and fiscal reasons. Nothing more radical than a 20-year phase-out plan needs to be proposed: allow the current dog population to live out its cycle; then, first, eliminate those industries that profit from breeding and selling tomorrow's dogs; and second, forbid dog ownership the way pet elephants or lions are forbidden.

The animals themselves will benefit most. Domesticated dogs are wolves with numbed-out brains. Due to centuries of being leashed and trained to fetch slippers, their minds have gone. They understand neither their own exploitation nor that city life is not for them. Genuine dog lovers, who oppose all forms of animal slavery, know that in man dogs have found their worst friend.