Well, I’m one of those people. I don’t believe in life or death in the conventional sense, so I see no problem.
Ask yourself, where is the locus of consciousness?
In the tradition I follow, it is not inside one’s head.
But, be that as it may, our bodies eventually cease to function. In practical terms, what is the difference between dying of cancer, or dying of murder? In both cases the thinking, the feeling, the memories run out and stop.
Saying that the difference lies externally, and depends on somebody else’s motive is problematic. If we are run over by a bus, does it really matter whether we drunkenly stepped out into the road or the driver drunkenly ran us down? The result is exactly the same, and we don’t care about it anyway.
In every case, we can say that we once woke up without having gone to sleep, and in due course we will go to sleep without waking up. Consciousness ceases on a nightly basis, and nobody has a problem with this. So killing another being is not a problem unless we have some attachment to outside forces beyond our control.
You touched upon the real problem with eating animals. If our treatment of them is cruel and distressing, then it is hard to justify their lives, and our own behaviour in inflicting suffering.
Pigs, for example, are social animals, evolved to live in family groups, forage in the forest, communicate with each other, and just generally have as good a time as they can. If we isolate them in concrete pens, force them to have an unnatural existence, prevent them from ever satisfying the desires that evolution over vast spans of time have given them, then we are not doing good work.
If we also make their deaths painful and distressing, then we add to our burden of guilt. Mind you, if pigs or other food animals were all living natural lives in the forest having a jolly good time, then death would also find them eventually, and it is unlikely that the process would be pleasant for them.
And, in practical terms, what is a humane solution? If all eight billion humans were to stop eating animals, and release them into the wild, then they would die in vast numbers because there are no vast mechanisms to care or feed them. They would be run over by cars, they would fall into holes, they would die of starvation and disease, they would be eaten by predators.
I see no problem with consuming ethically-farmed meat. Grass-fed cattle, for example. Cattle living lives of doing nothing much beyond having a jolly good time in the meadow with other cows eating the copious food made available to them. Doesn’t sound too horrid to me.