Harvesting =/= killing
Animals can't protect or defend themselves if they are born into a factory farm, and unable to escape.
Plants have none to very few basic senses, meaning it isn't even unethical to kill them.
Something is a live then it is not and you are responsible. How is that not killing.
Is it alright to kill if they can't feel it?
Death is death. No mater the magnitude. A single germ has as mush right to life as a human being. If, and that's only if mind you, you look at things from a purely rational way. There is no real difference between trying to quantify the difference of life between any to entities. So it maters not what species, race, or ideology.
You can not quantify life therefor all life must be equal.
One could even go so far as to suggest that to do other wise makes you the same as even the worst of men. Men who started and lost wars.
But that's only the result of one line of purely rational thinking.
There are other ways to quantify entities. From emotional ways to the way they impact others. To even the effect there death's have on there own species.
But they are all subjective ways. And it's up to each individual to make up there own rules.
My only problem with vegans is that they tend to ignore even the possibility of other lines of though.
I'm waiting for them to literally declare war of the rest of the world. Or try to form the peoples republic of green poopers.
Note: The preceding in it's entierty is more or less a joke, even if it is true. Don't take it to seriously.