I thought the same thing when I read that. When I was thinking of "integrity" from a security perspective (as you might in an article like this) it didn't make sense. But when I thought of it more from a pure data transfer perspective between say a browser and the application it made more sense. I don't think he's saying that it's safe from mitm attacks. (At least, I hope not....)
Think of integrity as fidelity. Encoding ensures that your information can be reconstructed accurately on the other end of a communications channel (whether that be the internet, to and from the hard drive, or even just to the person standing next to you).