Final answer:
Johnson may have chosen a graduation address to connect with an audience in a moment of achievement and hope, leverage the reflective atmosphere for a broader message, and use emotion and reasoning to enlighten and persuade listeners about important societal issues.
Step-by-step explanation:
Johnson may have chosen to address the American people under the guise of a graduation address for several strategic reasons. First, a graduation ceremony is a moment of significant personal and collective achievement, symbolizing the transition of students into a broader societal role. This setting can create a backdrop of hope and forward momentum. Secondly, the kairos—the opportune moment—of a graduation allows a speaker to tap into the mood of the community and the nation. It is a time when graduates and their families are reflective and thinking about the future, making them potentially more receptive to messages about the broader social and political context. Lastly, in such a setting, a speaker like Johnson can leverage a combination of pathos, wit, and reasoning to enlighten the minds and win the hearts of the audience, addressing pressing issues implicitly connected to the graduates' futures within a seemingly non-political forum.