First the academic approach: article written through a political coloured lens, which means it's not objective.
My opinion: politics develop. They did in the past and in the future this won't come to a halt. Being a politician myself I must say that I agree to the point on one-sidedness. But one has to bear in mind that it is very easy to blame politicians for how politics works. We are all part of the system: everyone can vote (taking a democracy as an example) and everyone thus deals with politics and shapes it.
People in general don't even want to know the facts, they live on emotions: "My neighbour is Moroccan so he's a criminal, look he ruined my car!" It's the way people think. They want to see their emotions and thought confirmed by politicians. That's why most elections (especially within Europe) have extreme results, mainly to the left.
In my opinion this shift is absolutely not the fault of politicians. Ok, some politicians are smart (that's why they get so many votes), they play the emotions of people. But after one term in office their voters will move to a more moderate point of view. Which has been scientifically proven.
Politics is all about the people, what they feel and what they think. Politicians only represent them, so they too will use language their voters want to hear. No votes, means no power. And, unfortunately, power and money is the fuel our world lives on.
I could carry on for ages about this topic. But I would say: we live in a democracy, in theory everyone has a say in politics. People don't want to know the facts, they don't want to read any background news, they have their prejudices and those are hard to get rid of. This is the true fact of politics. And as one of my professors stated in a lecture: "too bad, but remember that 70% of our voters is too0 stupid to understand what they are voting for. And besides that, they don't care what is going on."