Not true. Politics in this case is about evaluating the candidates. He is saying that one can, in part, see who a person/candidate is in their facial expression.
And that is a true statement. Case in point, take a look at Hillary's face. Isn't that exactly who she is? Pursed lips signifying a stiffness of personality. Her eyes showing us how haughty she is. Her wrinkled skin telling us how brittle and inflexible she is. Her chin in the air telling us that she believes she is better than us--that she believes she is a kind of royalty.
I guess that must be it. Trump thinks he is more royal than she, so he has to take her down a notch by making fun of her looks. Not a very mature or wise choice.