Not entirely true. It wasn't just their accents, it was their character and their movements. Watto's large hooked nose, beady eyes, and covetous personality evoke anti-Jew stereotypes, especially with the voice they gave him. Jar Jar's movements, bug-eyed, scaredy-cat behavior are pretty minstrel-show, and the "meso youso" speech pattern is the just the icing on the cake. Then there's the Nemoidians with their pseudo-Thai accents, far east costumes, duplicitous nature and diagonal (read squinty and slanted) pupils. I don't think I need continue, and I feel the urge to wash my hands.