[mod]

In many (most?) cases herbivores aren't taking the life of the plant.

Think of a squirrel, perhaps, and how it feeds on plants.

(Still don't agree with the GP)

[mikeash]

Good point, but I think squirrels are a bad example. They're not only taking lives, they're killing the babies!

[mod]

On the contrary, I imagine a lot of the nuts are planted by squirrels! In either case, many plants have an implicit bargain with animals: eat my fruit, but you must carry my seeds out beyond where I can reach and deposit them there.

Which happens when they pass through the gut, essentially.