See this report. While it also applies to ignorant Dems, however “studies have shown that Democrats now tend to be generally more educated than Republicans, making the latter more vulnerable to the Dunning-Kruger effect.”

“Perhaps this helps explain why Trump supporters seem to be so easily tricked into believing obvious falsehoods when their leader delivers his ‘alternative facts’ sprinkled with language designed to activate partisan identities. Because they lack knowledge but are confident that they do […] they are less likely than others to actually fact-check the claims that the President makes. This speculation is supported by evidence from empirical studies.”

Dunning-Kruger effect:

“In the field of psychology, the Dunning–Kruger effect is a cognitive bias in which people of low ability have illusory superiority and mistakenly assess their cognitive ability as greater than it is. The cognitive bias of illusory superiority comes from the inability of low-ability people to recognize their lack of ability; without the self-awareness of metacognition, low-ability people cannot objectively evaluate their actual competence or incompetence.”

“A new study published in the journal Political Psychology, carried out by the political scientist Ian Anson at the University of Maryland Baltimore County, not only found that the Dunning-Kruger effect applies to politics, it also appears to be exacerbated when partisan identities are made more salient. In other words, those who score low on political knowledge tend to overestimate their expertise even more when greater emphasis is placed on political affiliation. […] This occurred with both Republicans and Democrats, but only in those who scored low on political knowledge to begin with.”

“We should not lose all hope in trying to reach the victims of the Dunning-Kruger effect. At least one study found that incompetent students increased their ability to accurately estimate their class rank after being tutored in the skills they lacked. With the right education methods and a willingness to learn, the uninformed on both sides of the political aisle can gain a meta-awareness that can help them perceive themselves more objectively.”