Stilgar from the sietch got me thinking about this one - how do we get to decide which animals we can kill, legally and uncontroversially. The Bulgarian Law for the Protection of Animals(in Bulgarian, translation) was soon posted, exposing flagrant speciesism deeply rooted into the bulgarian legal system.
Now it's clear that such legislation raises more questions than it answers and it's bound to have critics. Humanity should be allowed to kill certain animals e.g. ones transmit diseases but on the other hand some are creepily similar to us to be used for cruel entertainment. There has to be a line somewhere - but how do we define it?
The classical school of thought here, advocated by luminaries like Douglas Hostadter, dictates that we should rate animals by intelligence and the most intelligent should be deemed closer to us, and thus - not eaten. This has also a lot of anecdotal support - quite a few vegetarians eat fish for example, for plenty of reasons, with "because they don't think" being one of them. Indeed, the more sophisticated nervous system an animal has - the closer to our experience of pain and distress it should be able to experience. Some problems arise though with the lack of reliable measure of intelligence - no one has managed to have a chimp and a dolphin play a game of chess yet, so we get to choose from the different sets of superficial criteria that give us different results. And of course the line has to be arbitrary - there is no such thing as universal maximum edible intelligence (this would make old people legal).
There is also the competing measure - cuteness. Kids nowadays grow up with children's books and films with super cool talking farm animals that don't stink even the slightest bit; kids can more easily imagine them being friends rather than source of food and stench. And with the rise of the internet with its feline obsession and vigilantism, cats became a no-no (sorry Alf). So, by natural selection optimizing for the cuteness factor some animals have found a new evolutional niche. This makes good sense - they live off the human society, which is profoundly stratified by physical appearance in many ways - better looking people of all sexes get a disproportionate amount of all the benefits, why should we then not discriminate against animals in the same way?
What we are seeing now is actually an evolutionary arms race for a part of humanity's waste resources between stray dogs and our anti-cuteness defence mechanism - the cutest of dogs have better chances to survive and produce progeny, thus cutifying their kind. If they do well maybe one day they'll achieve the level of protection that cats now enjoy and survive.