Some people do care about the plants though, such as Jainism. If you draw the line at plants - that's fine, but some others do not and are wondering why you arbitrarily drew that line where you did. Sure some may be joking around but its still a legit concern for some.
From what I understand, Jains are lacto-vegetarian [1]. Vegans draw that line further (because they also don't take milk).
As a human being, if you avoid eating plants, or things that eat plants, you die.
Jains don’t eat foods like onions and potatoes. But, so far as I know, this is on account of the bugs that may be harmed when harvesting soil-based plants.
I believe it's also as the onion or potatoe is the entire plant and when you eat it, it's gone. Verses eating a strawberry or Apple does not destroy the plant.