All things die, and it is safe to assume that for most, their death is not of their choosing - or else, why would they die? Therefore, in a way and to an angle, isn't it at least best that the waste of a life (a corpse; the remains left after life has ended) be used instead of cast aside, purposeless, and left to spoil?
I'm not sure what you're trying to defend. As I said before, if you want to eat corpses that die naturally, go nuts. If you're insinuating that breeding and killing animals for eating is just as natural a process as dying naturally, that's twisted.
There are obvious issues with both, which stem from the same way of thinking. That nature exists to be exploited and not for living in harmony with.
Nature isn't in harmony with ITSELF after all, it produced US. But seriously, nature is a struggle to the bitter, and yes, without exception, they are bitter, ends. There are ways to live that are more sustainable than others, but even the sun will go out eventually.