They knew it was offensive enough to have kept Song of the South locked in the Disney vault since 1986 (with the noted exception of making Splash Mountain itself).
Yeah and I think the decisions when Splash was made to avoid uncle remus and only focus on the characters and so forth was a very deliberate decision to hopefully keep what was considered good and avoid the known problematic elements but in the end I think it's connection to SotS and Uncle Remus Stories was too much to overcome.
It would be nice if at some point the stories of bair rabbit and fox could be repackaged in a format that is respectful to their original origins but at this point I think disney has too much baggage on the subject to be able to be the ones to do that.