Sometimes, when you're speaking with an illiterate person, you might notice the difference between how illiterate and literate people talk. You may even find that the illiterate person speaks with more wisdom than the literate one, and you'll prefer talking to them. Some literate people went to school, but the way they behave or speak can be so disappointing that you begin to wonder, "Did this person really go to school?" Because they don't know how to speak or respect, even illiterate people can speak and are respected more than them. Also, to me your friend supposed not to utter such statements.