The whole racism thing with Jar Jar Binks was just something overblown by people who look to find racism in everything, who aren't happy unless they're offended. It's like when the protest groups cry offense at Native American sports mascots and somehow they speak on behalf of the Native Americans who aren't offended by the mascots.
Skids and Mudflap were more noticeable, but do you take into account that one actor was white and the other was black? Does the black actor have no say in the nature of his own performance? Does it matter if the actors were doing a lot of ad-libbing and going off with the characters? Yet the simple fact is that they are robots. When you have white characters acting all gangsta like in Havoc or Alpha Dog, is that racist toward blacks?