Zaroff states, "I'm a hunter, not a murderer." How does this fit in with Rainsford's hunting philosophy in The Most Dangerous Game?

Zaroff and Rainsford, the main characters in "The Most
Dangerous Game," share a passion for hunting.  Rainsford is an expert in the field,
having written many books on the subject, books which Zaroff has actually read,
ironically enough.  Rainsford considers it a sport which humans are more or less
entitled to because of their superiority to animals, who he perceives don't really
notice or feel anything when they are being hunted (a philosophy which changes fairly
quickly when he becomes the hunted one).  Zaroff is a cold, calculating killer, despite
what he might say, and he conceives the idea of hunting human beings as being more
challenging to himself, as well as being perfectly OK since he hunts people that he
considers to be socially inferior.