[tomatowurst]

> It isn't based on individual age.

It is. you are using a special anecdotal case in a family situation (that same person would use honorifics towards their friends who are much older) to negate the rest of Korean society that uses one's age to decide who is above and below you, and the necessary honorifics. DK effect is quite laughable to see from a non-Korean.

I invite you to address your professor or sunbae or the elderly without honorifics and see their reaction. You wouldn't be able to use your race card very long.

[bmitc]

From my vast expertise (sarcasm) from watching Kpop, Korean variety shows, and Korean movies, the whole age thing is pretty rampant and adhered to, at least from those lenses. I mean, they have literal discussions while shooting regarding asking direct ages in order to speak "familiar" or not. It is pretty weird and arbitrary, especially with the way Koreans measure age.

[tomatowurst]

those media you consume are a reflection of society. koreans use honorifics with strangers until they signal they wish to communicate casually and usually its completely subjective. somebody will only differ by mere months and demand you use honorifics (bullying). somebody will differ by few years and do not enforce it. its completely subjective and adds to the stress of interaction between strangers.