The assumption I pose is that (given the very generous notion) if plant life is equivalent to animal life, and destroying life is undesirable, then eating animals is worse (in this regard) than eating plants because it destroys _more_ life.
A small detail: While destroying more life this process is _creating_ more life at the same time... Not that is has to matter.
Its pretty complex. For instance, growing plants means essentially sterilizing the ground under them, killing tens of thousands of small rodents. Millions of insects. Billions of soil microorganisms.