Earlier quoted context omitted.
But I bet you these people sure can leetcode!
While I've met plenty of terrible developers from the best universities and with the best grades and interviewing skills, people that was easily outclassed and outperformed by 3-month bootcampers, I can't lie crappiest one are much worse, people who struggle to implement very basic algorithms such as Fizz-Buzz.
If you are given really hard questions in an interview or they ask for dumb invert binary tree like questions. It is most likely that person who interviews you is lazy or does not want to hire you but have no choice but to interview you.
I beleive pair programming interviews are the best. As they can be 1) Time limited so you don't take home and waste your time. 2) Can be a portion of a real world problem.