A significant portion of the electorate believes that the government is hiding aliens, or that the political leadership are all secretly lizard people (whether this is meant literally or as a metaphor for Jews or whether they think Jews are secretly lizard people depends on the person). There are vast and necessary government functions that most of the electorate doesn't understand or doesn't value or completely misunderstands.
Even on hacker news I frequently see people completely misunderstanding how, for instance, scientific research gets funded in the US. And the readership of this site is far more likely than a random sample of Americans to know about scientific research.
Dismantling chunks of the government based on the ignorance of some portion of the electorate is just bad policy.