It is looking like telling lies is the prerequisite of becoming a politician. As a matter of fact, there is a way you will tell lies that people will start suspecting you to be a politician. How we get to this point in human history is what no one can explain.
How is it that no one can explain? It's quite simple to explain: people do like liars. People ask to be lied to. People have a thing for liars, maybe because human beings tend to feel attracted by what is similar to them, that is, to what they identify to. Politicians and governments are just the reflex on the mirror of the population they represent and rule.
I don't know about your country but in my country, politicians buy over media empires to sell lies and propaganda to the public... I know this is not peculiar to my country. This may be the reason there is a growing distrust between the leaders and the followers.
Well, after all human beings still have 'free will'. If they are consuming or buying such lies from the media, it's because they consciously went for that. I don't buy what I don't want to consume. They must feel fascinated by one aspect or other of those lies (or of the liars) to keep buying them.
But is politics supposed to really be about lies? Why is the polity dominating by propaganda?
It wasn't supposed to. But everything in this wicked world is subverted from its original purposes. Politics is dominated by propaganda or illusion, because politicians know that is how they can divide to conquer.