Wikipedia quotes a few philosophers on the principle of charity:

Blackburn: "it constrains the interpreter to maximize the truth or rationality in the subject's sayings."

Davidson: "We make maximum sense of the words and thoughts of others when we interpret in a way that optimises agreement."

Also, Dennett in The Intentional Stance quotes Quine that "assertions startlingly false on the face of them are likely to turn on hidden differences of language", which seems to be a related point.