snowflake, I think my Captain Know-It-All former co-worker, Mike, would fall in the same category as your parents! He was pretty insufferable when he was studying for his PhD, I can only imagine it's gotten worse with the unwashed masses now that he's actually
a doctor (fortunately not around us anymore!). Though of course when everyone
is a doctor, just having a PhD does not impress people.
The thing was, he was pretty smart, and actually correct about certain things that were within his interest. If it was outside his interest, say a genre of literature he didn't care for, obviously it was unimportant.
Naturally, his political leanings were the only sensible opinion anyone could have. He was continually startled by what other people didn't know, but felt it was his moral duty to inform them--once a random stranger on the street was treated to a lecture about nuclear physics (NOT our area of expertise) because he made an off-hand comment to Mike involving a common misconception about nuclear energy. Mike was shocked the man didn't know the details and expected the rest of us to commend him for enlightening the guy.
He was from New England and believed that everything good or important had been invented in New England; if we had it here in flyover country, it was because it had come from New England, and if we didn't, well, that just showed how far behind we were.
He was a bag of eye-roll, actually.