The people complaining about Elmer Fudd hunting for food clearly haven't watched many Bugs Bunny cartoons. "Wabbit stew" was always what Elmer was after when he went hunting — it was one of his catchphrases well before this cartoon was made (example: "Hare Tonic" from 1945, directed by Chuck Jones). It's part of what makes that line so funny in this cartoon! Jones didn't ret-con Elmer into being a vegetarian until "Rabbit Fire" in 1951, so it's hard to understand how McKimson should have been able to foresee that four years earlier. And the mention of Elmer as a vegetarian was just for the sake of a gag anyway, not to establish a running character trait — after all, in 1953, Jones was back to having Elmer hunt for "wabbit stew" in "Duck! Rabbit! Duck!".
As for Bugs being mean-spirited, the same comment applies — Bugs was always somewhat of an amoral character in the 1940s cartoons, even going so far as to be an outright jerk sometimes (particularly in his earliest appearances, such as "Elmer's Pet Rabbit" and the Cecil the Turtle shorts). Jones didn't make him into a goody-two-shoes type character until later in the 1950s.
And of course it's not like the WB cartoons ever cared much about canon or continuity anyway. Next thing you know, someone will be complaining about inconsistency in "Duck Dodgers in the 24 1/2th Century" because Daffy Duck usually isn't a space marine.
