I believe some of Django was an homage to old spaghetti westerns, and while there was probably more blood in Django compared to those older movies, the body count probably wasn't that different. I'm sure if you look you'll find that there are tributes to other genres for IB as well. The cathartic interpretation is just what I came away with after watching it, mainly from the final scene.
Tarantino is a director that likes to tell stories while paying homage to other films and genres that have influenced him. That's just what he's decided to do and he pretty much has free reign to do what ever he wants now. I think he's an excellent story teller and a master of dialogue, and if you look past the goriness, there are some pretty great stories underneath. And I don't think it's really fair to try and say he's not producing "art". Art that you don't care for is still art.
He does have free reign, no arguments here - and I think he has some great stories and great dialogue, I just think he's turning it into a joke with the gore. I didn't say the entire movie wasn't art, but there's nothing artistic about the gore scenes. Why ruin an otherwise fantastic movie with some of these scenes?
Let me flip it for you - explain to me how Django was made better with that last scene? Did it enhance the previous dialogue between Waltz and Foxx? Did it improve the movie in any way, and (if so) how? Directors leave the crap that doesn't help the movie along on the cutting room floor - I just don't understand why, other than to provoke and shock, he wouldn't have omitted the last ten minutes of Django.