It may indeed be the case that the candidate promised one thing and the voters acting irrationally (or correctly assuming he's a liar) voted with an expectation

It may indeed be the case that the candidate promised one thing and the voters acting irrationally (or correctly assuming he's a liar) voted with an expectation of him doing the exact opposite. The GP, however didn't say anything about voting. He was talking specifically about the mismatch between campaign promises and actions taken once in office.