One less conspiratorial but more pernicious angle, is that attacking things that are good but complex is a great strategy for troll politicians who don't care about the success of their country but just like the attention.
See Brexit, and free trade in general.
It's a good way to get "the establishment" to gang up on you and defend something complicated while you present simple but wrong alternatives and promise the world.
I also think he's up for sale (as are all the other similar politicians) to a multitude of buyers, foreign and domestic.
"For every complex problem there is an answer that is clear, simple, and wrong."
The issue is that the stupider the politician, the more likely they are unable to understand why their clear, simple answer to the ills of the world is also wrong.
Brexit, whatever is happening in the US, is caused by narcissism (a common trait among politicians) paired with a great deal of stupidity and ineptitude, not only among politicians, but among the populace as well.
For Brexit in particular, it seems clear to me that EU politicians, but the UK ones in particular, used EU as a scapegoat for unpopular economic policy that they themselves actually want, but can't justify effectively to their constituents. "We can't help it, it's an EU requirement" when leaving out that in the EU, their guys totally supported it.
That was bound to backfire at some point or another.
I think you're right that politicians prefer not to defend complicated (and possibly good) policy to the public. But if they choose easy ways out to avoid it (and they do!) then they're to blame too when it collapses. To blame the public for not blindly trusting them won't do.