In a nutshell, the incompetent lack the skills/ability/knowledge to recognize that they lack the skills/ability/knowledge, and that leads to them to overestimate their skills/ability/knowledge, where as the competent underestimate their competence which leads them to overestimate the competence of the incompetent.
That's both sides of the same coin, now that I think about it.
Liberals refuse to admit when they are wrong, essentially 99.44% of the time, and go to all sorts of contorted machinations to avoid admitting that denial of each failure is something other than that river in Egypt.
https://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
It's fighting me. I swear, it was there.