In Korea, age is the most basic factor to determine seniority. For this age-based hierarchy to be neutralized, there has to be a confluence of some very unusual circumstances.
Re the information about the flying pilot being ahead of the trainer at flight academy. I'm not sure how reliable that is but had that been the case, it certainly would not have stopped the older guy from speaking up. Please keep in mind, at least for the flight, he is the "teacher" and in Asian countries, teachers are respected in ways that American educators can only dream of.
The Korean airlines have had a terrible record for quite a long time until 1999 when the FAA and EU threatened to block them from their airspace. They have had accidents with fatalities precisely conforming to the cultural issue under discussion. You did say you wer familiar with Gladwell's book.
The CVR supports the crew not communicating for the 2 minutes prior to the crash even as the approach was anything but airline quality and not corrected or commented upon until 7 seconds before crash. 3 pilots in the cockpit, one new to the type, one new to the position, and one very junior to the others. It fits with what other expats have seen recently among Korean crews for KAL and Asiana. It fits with the Japanese/American fellow detailing the numerous interweaving levels of seniority/deference as he has lived it. But if it makes you feel superior and civilized to believe the culture witnessed by the FAA, EU, expat pilots and instructors and consistent with the CVR is just a figment of mine, feel away.
Just because it's taboo to think something in polite society doesn't mean it doesn't exist.