Having two older brothers who are famous trial lawyers, I can attest that it's both an effective line of questioning and a deeply infuriating one. What I learned is that up to a certain point, it's feigned ignorance probing whether one knows a principle behind a stated principle. Beyond that point, though, you can basically make shit up and they won't know the difference. Come to think of it, this is also the sleight-of-hand pulled by LLMs when you ask them for more and more detailed answers. The trick is knowing when your interrogator no longer knows the answer.
[edit] Also, in my family, you'd ask Dad these questions. And if he didn't know the answer, he'd pull out the Britannica, and have you look it up, then go over it with you until he understood it well enough to explain it. "No short answers" was his motto. (He was also a trial lawyer). Most people are just not equipped to handle cross-examination, and it's scary for them... but the primary reason is that they never learned to admit when they don't know the answer.to a question, and that admitting you don't know is not a failing, but actually a strength, especially if it impels your curiosity to go find the answer.
[edit] Also, in my family, you'd ask Dad these questions. And if he didn't know the answer, he'd pull out the Britannica, and have you look it up, then go over it with you until he understood it well enough to explain it. "No short answers" was his motto. (He was also a trial lawyer). Most people are just not equipped to handle cross-examination, and it's scary for them... but the primary reason is that they never learned to admit when they don't know the answer.to a question, and that admitting you don't know is not a failing, but actually a strength, especially if it impels your curiosity to go find the answer.