[The Jungle Book 2016] why doesn't Baloo just kill Shere Khan?

In original story and 1967 Baloo was shown and described as a sloth bear a bear much smaller (200-300lbs)that fights and fends off tigers. Hence why he's able to fend off Shere Khan but eventually loses in the end. However in the 2016 remake Baloo is a Grizzly and pretty big one at that so I always wondered what the big fuse was. I know it's the point of the story but having Baloo the at least 700 pound grizzly told that Shere Khan a 350 pound half blind tiger .Will kill him despite the fact Baloo could probably snap his spine with his paws. I don't know I always found it weird.