I don’t see it as racist. Someone raised in India whose tongue was trained on a different language is going to sound that way regardless of what they look like. Assuming that everyone who works in a convenience store sounds like this is racist. But being an Indian immigrant is part of the character’s back story. The color of the skin of the voice actor is irrelevant. What if Homer was voiced by an Indian man doing an American accent? Bart is voiced by a woman acting as a boy. Is that sexist?