Because people are stupid

After the first goat was slaughtered and the first fish was fished! The animals, sensed the severity of events and called for a meeting.
The meeting was attended by one representative from every class and subclass of animal.

All animals were angry. The goat was angriest. He said that his community had been wronged and severe action against humans must follow. The fish did not attend the meeting because they protested that the venue, being on land, was unsuitable for them.

The Cat was unanimously elected as chairman of the meeting. He purred and presided over the matter. He concluded that if humans enjoyed the taste of goat, they would soon venture out to try eating other animals. And this, was naturally, a cause for alarm.

The animals could not really come to a conclusion and there was disarray at the meeting.

The meeting was adjourned and the crowd diapered. Mr. Cat went over to his community and addressed them saying "the meeting did not reach a conclusive end. We could not agree on anything."

All animals were furious. Why wasn't anything being done against the humans? How could savages roam around freely eating animals unpunished!

The next day, Mr. Cat put forward a bill, he called it the "domestic bill". He suggested that all animals should let go of their wild ways and submit to humans. He said that if animals allowed humans to develop a sense of emotional companionship with them, they would not eat them.
Mr. Lion was enraged "submit to humans, ee'ez barkin mad aint'he?"
The Dog was offended by this statement. "What does he mean by barking mad?"
"We cannot argue over trivialities" said the Cat
The Horse spoke and said "I find it odd that anyone should suggest that we should submit to humans! Is it not demeaning to be domesticated?"
A twitter broke out in the room. Most agreed, a few disproved.
The Dog said "I'd rather be petted than chewed"
Mr. Elephant said "how can we submit to someone who is smaller, punier and weaker than we?"
Mr. Lion said "we'd rather fight for our lives than submit to humans"
The cat spoke "but not all animals in this room, are as strong as you." A murmur broke out.
The lion stood up and twirling his mane said "I cannot stand the thought of being at the service of a human being. Hence I choose to abandon this meeting. My community will deal with the matter how we always have, by fighting for our lives"
The lion turned his tail and walked out, the elephant, the grisly bear, the crocodile and several other wild animals followed him out.

The horse said "it is below us to be gushed upon by humans. We would rather work for our living. Hence we want to introduce the domestic working bill"
The pig spoke "but what work can I do?"
Again a commotion broke out.

The horse said "I chose to leave this meeting too, my community will deal with this how we always have, by being of use"

The horse galloped out. The donkey, oxen and cow followed him out.

There were few animals left in the room now. The dog and cat were fighting strongly for the domestic bill. The rabbit supported them. The pig decided to abandon the meeting and announced that his community would find an innovative solution out of this.

The bill was passed. Cats earned the better share of things since they purred around, did absolutely nothing, got free food and were not eaten. The dogs had to put in some hours of service but by and large they were pleased with the outcome.

A few days after the passing of the bill, the pigs and cows requisitioned for a meeting. This was attended only by the goat, the chicken, the cow and the pig. The cow's grouse was that despite labouring around by providing milk and toiling on the field all day, humans were slaughtering them for meat. The chicken were annoyed that despite providing eggs, they were being killed for meat.
The pig was elected as the chairman of the meeting. He said "I propose we pass a hitherto unheard bill. I call this the Forbidden due to unholiness Bill"

"What is that?" Inquired the cow
"We must convince humans that we are disgusting, hygienically. We have lice and ticks. We harbour various diseases and are therefore unfit for consumption."
"Humans are not that stupid" said the cow "they will skin us and eat the flesh. They don't care what roams on our hide and skin"
The goat and chicken agreed.
The pig persisted "but if they are forbidden by holy doctrines. They won't go against it"
The other animals found this far fetched. The pig finally said "then I'll leave this meeting. My community will
Pass this bill and we will convince humans that it is against their religious beliefs to eat us".

The cow being slightly inspired by this said "while the pig's proposition was not altogether loathsome. What irked me was to convince humans that I'm unhygienic. But I like the prospect of convincing humans Im too holy for consumption"

The goat and chicken exchanged glances and were unsure how to respond. The cow added "my bill is called the Forbidden due to holiness bill"

"This is a long shot" said the chicken. "Why would you be holy! You don't even look remotely divine"

The cow smirked "what do humans love most?"
"Their wives" said the goat
"No, their mothers" insisted the cow "if I can convince them that I'm their mother, they'd never eat me"
"Why would they consider you their mother?" Asked the goat
"Because humans are stupid and are driven by sentiment rather than reasoning." Having said this the cow left the room.
The goat and chicken were alone and had decided on nothing.

It later came to the knowledge of the entire animal kingdom, that the pigs had played dirty. In their "forbidden due to unholiness bill" they had somewhere managed to recommend and advocate the eating of goat. Hence goats were slaughtered unceremoniously in the name of the same bill that protected the pigs.

Thus, the chicken being least assertive and least intelligent continued to suffer as no bill protected it.

So the horses labored, the lions dwindled in number and the dogs guarded and served dutifully. All awhile they abused the pig community for playing dirty with the goats.

Not one among them, ever realized that the first bill that was introduced by the cats compromised them all. The cats traded them into labour, extinction and human consumption. The cats thieved around, weren't loyal, they got humans to cultivate bonds with them without ever reciprocating the sentiment.
They only purred and brushed their backs against the feet of stupid human beings and were never eaten.