It's the other way around: you need to prove that what he says is merely feel-good baloney.

Otherwise, every person is insincere, including both yourself and I.

Side anecdote: While I haven't met and talked with the guy in person, I know a person who has. Her impressions of him was that he was an honest man who cared about his country.

Take what people say with a grain of salt unless there is reliable source that backs them up.