It is a stereotype that certain ethnic groups hold certain occupations. Look at the character in The Simpsons who works at the quickie mart as an example of a stereotype used as humor which really is a slam against someone's ethnicity. I guess since Democrats are basically racists such 'humor' is used in their campaigns.
Apu is the salt of the earth, beloved by all, fighting off villains as a small businessman. What's negative about that? I relate to Apu, as does anyone watching the Simpson's with a sense of humor. How about Burns' stereotype as the rich white man running a nuke plant, isn't that more a negative stereotype? (I relate to Burns as well).
I wonder if it would have been equally offensive if she said Ghandi answered phones at Dell's customer service center.