Oh, there are plenty of Disney characters that we would simply be aghast by today, but that is less a product of Disney himself and more a product of the time in which those particular characters were created. Keep in mind, average joe folks - not Klansmen or nutjobs, but regular citizens - in the US used to be 100% convinced that blacks were born with tails. This is also a society that used to require blacks to eat at separate counters and drink from separate water fountains. So portraying them as buffoons in movies? Well, gosh, what's the big deal?
Now, obviously, we can see what the big deal is, but at the time? Not so much.