Why?

Because elephants seem to be perturbed by and charge toward metallic sounds, but the firing of a gun creates a generalized BOOOOM that is hard to pinpoint. So the theory is that it is safer although slower to quietly reload without ejectors because the elephants are less likely to know where you are.

Like all other theories, it may have little application in practice. Most people will drop their elephant with one or two shots, and therefore could play an electric guitar while reloading without causing any trouble.