The idea of taking exams in order to play a part in the running of society is peculiar to meritocracy.
The problem isn’t so much that voters can’t be trusted with their vote
That seems to be the problem for Jeremy, who implied as much.
but that politicians and leaders can’t be trusted not to lie.
That's never been any different.
If there's an issue of trust in play, it's in trusting people to know when they're being lied to. The general view of the political class and the esteem in which politicians broadly are held suggests that that trust isn't misplaced.