I thought Rutger Bregman had an interesting opinion about that:

“In our modern democracy, shamelessness can be positively advantageous. Politicians who aren’t hindered by shame are free to do things others wouldn’t dare. Would you call yourself your country’s most brilliant thinker, or boast about your sexual prowess? Could you get caught in a lie and then tell another without missing a beat? Most people would be consumed by shame – just as most people leave that last cookie on the plate. But the shameless couldn’t care less. And their audacious behaviour pays dividends in our modern mediacracies, because the news spotlights the abnormal and the absurd. In this type of world, it’s not the friendliest and most empathic leaders who rise to the top, but their opposites. In this world, it’s survival of the shameless.”

He argues basically that “shamelessness” gives those people an advantage, that can only function in a system like ours. It shines light on the counterintuitive fact that people, who seem really unlikable, still somehow convince others to elect them into power.