Cats and dogs are domesticated and raised to be pets for humans. The others are raised strictly for food.
Why is it deemed acceptable in America and the UK to kill and eat pigs, cows, and chickens, but not cats and dogs? Why do cats and dogs are more protective rights than other animals?
Two quotes from a great article:
http://theweek.com/articles/444996/why-shouldnt-eat-dog-not-even-once
"But the reason we shouldn't eat dogs is related to the same reason it is more heinous and hateful to burn a synagogue than a community center, or that it is more of a violation to burn down a man's home than the two rental properties he owns of an equivalent dollar value. The spaces, objects, and even animals we sanctify with our respect, friendship, and time really do enter into different moral categories. It is not inherently evil to smash a picture, but it is a gesture of hatred to tear a beloved family photo."
"....dogs,.... Have been made by hundreds of years of history and culture into icons of industry, creativity, friendship, and love."
Because farm animals are raised for the sole purpose of food .. And have always been for thousands of years. Cats and Dogs were deemed as 'working' animals, they had jobs (controling vermin, protection, alarm system, herding, etc) and eventually deemed as pets as those jobs became obsolete.
We have become a society that frowns on consuming household 'pets' as food .. And are even becoming more aware of the need for change in the treatment of animals destined for slaughter, as well as the general care of all animals in captivity .. Emphasis on 'working on' .. We still have a long way to go.
In MY perfect world .. Cruel and torturous treatment of ALL animals will be completely obsolete, and we will become a 'kinder' society.
A society can be judged by the way they treat their weakest and most vulnerable.