|Humans are extremely wary of the obviously inauthentic.|
Donald Trump, being a narcissistic sociopath, is another whole level where he believes and means the nonsense he says, when he says it - and two days later he sincerely believes and means something different which can be completely contradictory. And to him, they're both true - just not in reality.
Michael Bloomberg said, "I know a con when I see one" which captures the truth of Trump. Because good con men sincerely believe their own lies when they're telling them, just like Boris Johnson does.
To me Donald Trump was and is the same narcissistic new-money buffoon he was in 'Spy' magazine in the 1980s. For others he was the Donald Trump character he played on "The Apprentice" which has little to do with who is he - the character on theTV show was who Donald Trump wished he was.