Killing power" has many components: shock, energy, penetration, expansion, "momentum" (per Ackley), and TKO. Anyone who picks just one aspect of the overall equation and chooses to pretend the others do not exist, exposes his ignorance of the equation as a whole, IMHO.
I'm not ignoring any of this, (except the TKO) yes it all plays into the animals demise. this whole debate was whether energy kills or not. I just think to many people emphasise on energy. energy sells guns but it doesnt knock anything down.