The difference is that the crows in Dumbo clearly were stereotypes of Southern blacks-- there was nothing crow-like about their voices, they were simple racist caracatures, with clearly identifiable accents and speech-patterns, and idiomatic expressions clearly associated with a particular group, reinforced by the colour of the bird. Even in print, there is no ambiguity at all about the implied race of the crows: “But I’d be done see’n about everything when I see an elephant fly.”
The alleged “stereotypes” in Star Wars, (with the exception of Lando,) differ from this considerably. A racist stereotype of an Asian is, usually- Slanted eyes. Buck Teeth. Yellow Skin. Substitution of consonants, “L” for “R”. Exaggeration of honourifics. Confusion of pronouns. Neimodians have none of these charactaristics – it’s not that they simply don’t resemble asians – they don’t resemble asian stereotypes. As an exercise, describe any of the alleged racial stereotypes in Star Wars, without simply saying “Neimodians sound like asian stereotypes” or “Jar-Jar sounds like a west-indian stereotype.” Define the stereotype, and then describe how the character fits it. It seems to me that the Gungan gimmick is mainly about appending pronouns with “-sah”, and speaking in baby-talk. “Ex-squeeze me…” “You-sah gonna be in deep doo-doo.” This is “Jamaican” how? I don’t get it.