[GolangProject]

Well, I think you'd have to accept the Schopenhauerian worldview (or something similarly pessimistic) in toto, that sentient life involves a surfeit of suffering and conflicting desires that cannot possibly be reconciled, in order to accept the general asymmetry. A short quotation can, of course, only give a glimpse into that: it should be understood as rhetoric more than an analytical chain of reasoning. One animal eating another is absolutely central to the system of nature, since it's how the system sustains itself; the pain of one creature being hunted down and eaten is necessary for the other creature to survive, and yet the pain of dying is obviously greater than the satisfaction of eating.