You guys are pretty funny arguing simple physics.
First off an arrow kills by hemorrhage, not the same as a bullet.
The way a bullet destroys the lungs heart and nervous system as stated is by energy deposition and the resulting temporary cavity created by a bullet. Surely you have seen a ballistic gel shot and the resulting disruption of the gel at distance from the actual bullet path. This is a direct result of the energy of the bullet. Do you need a fast bullet to kill? No, you can kill with a slow pointy stick as eluded to. That was not the question was it? It was about the .270 being bad medicine for moose.
As for your varmint gun slinging rounds at 3000 fps, that would be devastating on anything you shoot with it if the bullet will stay together. However, I doubt that a light varmit bullet will maintain those high velocities at distance. That is the nice thing about heavy bullets, they will maintain their velocity over distance.
Speaking of varmit rounds, the military and police fight with small high velocity bullets. They get it.