Answer and Explanation:
He takes on a more cheerful tone to make the interview more "palatable" to the public, that is, he knows that the interview is seen and heard by the most different types of audience, so to make the interview lighter and more comprehensive for everyone, allowing his words reach the most varied types of people, he prefers to use a funnier and more relaxed tone, allowing empathy between him and the audience and a greater acceptance of the ideas he has to speak.