Don't you also draw a line when you choose to eat plants?
I think there's a reasonable distinction here. You would presumably also draw a line between a conscious human and a brain dead human that won't ever be conscious again. As far as we can reasonably tell, consciousness requires a brain. Dogs and pigs have brains, so maybe we shouldn't torture and kill them on factory farms. We can also see them suffering and measure their physical reaction to it.
Of course there's a possibility that plants have some kind of consciousness too, but 1. that's speculation and 2. there's no way around farming them, as you have said yourself:
Untill humans develop the ability to photosynthesize, we are going to have to eat other species, there's no way around it.
Farming animals will always require far more plant deaths than growing plants for human consumption. These animals have to grow for months before being slaughtered and literally eat tons of animal feed in that time.
Therefore, plant-based food minimizes both animal suffering and deaths as well as plant deaths.
I'm not convinced that plant deaths are an ethical issue in of themselves, but farming has environmental implications so it makes sense to minimize the food that needs to be grown and make the farming as environmentally friendly as reasonably possible.
the vast majority of plant matter fed to animals is waste product. they eat parts of plants that people can't or won't eat. so those plants are killed first for us, then the animals. and the point of the plant objection is not the amount of suffering, but the fact that no one cares if plants are killed, and only vegetarians and vegans care if animals are killed
This is wrong. Nearly all (source) of the soy the Amazonas gets destroyed for is animal feed. We give about one third of the global grain we produce to animals, we could end global hunger if we'd give it to humans. Plus we could reforest vast regions, so we don't die, as a species. Go vegan please.
you're wrong. soy is a great example: about 85% of the global crop is pressed for soybean oil. the byproduct would be industrial waste if it weren't fed to livestock
Soy cake can be used to produce textured vegetable protein (meat alternatives), tofu, tempeh, soy milk, protein powder, biofuels and bioplastics, for example.
Calling that industrial waste is just a complete joke.
The land could also be used to grow other crops for human consumption.
Soy cake can be used to produce textured vegetable protein
but most people don't want to eat it. you enumerated many of the uses it has been put to, but the fact is that we produce far more soy cake than is used in those other industries, and feeding it to animals is a good use for it.