"Not only are plants alive, they have feelings, and talk to each other. Even worse, we often don't kill them completely before eating them."
So go on to establish PETPV--People for the Ethical Treatment of Plants and Vegetation.
"A lot of them actually "want" (yes I know, I dislike anthropomorphism as much as the next deity, we're talking selection pressure success here) to be eaten so we will later deposit some of the seeds in a pile of damp compost. Evil human beings have developed seedless grapes, but the principle is the thing."
And seedless watermelons. And practically all bananas are seedless, too (the Cavendish is cloned).
"The human population that could be supported on a fruitarian diet probably isn't that high but the death rate from PETA being allowed to mandate it would certainly do wonders for soil fertility for a few years."
There is an ongoing argument that one could easily support many more people by turning over grazing land to crops and letting the hillsides go wild again to support the ground-level ecosystems and prevent monoculture. But then, that starts another argument about the nutrients that we can ONLY get from animals.