Its hard to define why in this case, but I suspect at least, the focuse usualy is trying to change the way comon people consumes food, or wear etc, instead of trying to make people to change the way humans produce food.
I think even if the entire mankind was vegan, and no one weared animal derived wear, still animals would be killed exactly the same way and almost the same manner under another excuse. the problem is not eating animal food, but the way you treat animals. I had discussions with a friend about this topic. and it seems usually the focus relies, in feeling guilty by the death or way an animal is treated, because you consume such food.
but ironically, almost everithing in life comes from the suffering of someone, even when we buy a home, or house, in many countries the poeple who builded it, spend lots of hours of life, to receive misery payment, in which they will never be able to own their own home in their lives. or the expensive shoes people wears are usually made by children in third world countries. and so many others things more.
usually people want to eat meat, and they dont care about the suffering of the animal, but less about the man who has to slaughter it.
I think the problem with people is not understanding the measure of things in life. its like you just dont care in inflicting pain to an animal because you eat it, or you jkust care to the extent of not eating it, and letting its meat to rot in the market for nothing.
I learned from poeple who grew in the country, and even from the bible, that the matter if you consider the animal you growing, is to care about him as a living creature, even if your going to eat him. and this is the problem with poeple, its a thought they are taught not to consider, cause they are thaught that just not to eat meat, will solve their own guiltiness, but usually for God is better someone who gives thanks for a sacrifice, than someone who just feels better than another, because doesnt do this or that.
and I think the problem sometimes is understanding the concep of sacrifice, that in this absurd atheist society is forgotten and ignored.