People generally reply to this with "He was making a point. He wasn't saying he couldn't be trusted, he was saying 'I could be anyone'"

I don't get it. I think he meant exactly how it looks on paper

Fine in isolation but then he proceeded to act in Dastardly ways for a decade.

Why is it fine in isolation? Should you not get exactly the pushback you'd expect from saying that? As a clear joke, maybe less. I don't think he was joking though