We know a lot less than we think about the world

The difference is that the complexity of a piano is an inevitable feature of it (at least until someone invents a simpler version). But it is far from obvious that the complexity of the tax code, or the EU, or how schools are funded is functional.

These political systems may be complex precisely in order to confuse the voters, in which case it is quite rational for the voters to try to push for simplicity - for example, avoiding the complexity of the EU by simply leaving it.

The article is jarring, as it seemingly describes the Dunning-Kruger Effect interspersed with other related cognitive biases, which are generally applicable to the society as a whole; which then is contrasted with the mile-wide-inch-deep philosophy of politicians, to segue into the hook of 'Simplism'. The vague 'elephant in the room, suggests that there will be more bull in the shop' type of writing is devoid of any incisive views. There is no identification of the group that are most accused of being simpletons, nor is there any real explanation of how/why they came into existence. Whilst politicians are dismissed by the virtue of having mysteriously acquired a new skill-set, even though it is their trade-craft to deliver platitudes, repeat meaningless slogans, spout ambiguous words, peddle fallacies, twist statistics, promise bottled unicorn farts etc.