When you're raising a brilliant kid and want him to have a good academic work ethic, you have to hold him to standards that don't have any other pragmatic justification. They raised their standards to a level that made him work hard in school, which is perfectly appropriate. There are other things they could have done, such as home-schooled him, pushed him to excel at academic extracurriculars (if they were available), or forced him to abandon his friends and attend university early, but they may not have been aware of those options, and pushing him to do well in school is a decent approach. Holding a kid that smart to "reasonable" standards means allowing him not to work at all, which means he's in for a big shock when he gets to the real world and realizes that sitting around being 20% smarter than everybody else isn't actually rewarded (or rewarding).

He doesn't say precisely what he's complaining about. Since everything else seems to have worked out well for him, I can only speculate that maybe he has some personal problems he attributes to the way he was raised -- but who doesn't? It's much easier to understand how our own problems could have been avoided than to imagine the problems we would have had if we were raised differently.

P.S. Any other mistake parents make -- like making a kid feel deficient or unloved -- is separate from holding them to high standards and making them work hard. If a kid's feeling of being loved or being a valid human being hinges on what his parents say about his grades, they've screwed something else up already, and they can't fix it just by giving a thumbs-up to his grades.

P.P.S. Just wanted to clarify I'm not presuming to talk about details of the real Kim here; I'm talking about a situation we've extrapolated from a few words in the article, which is as good as hypothetical.

Telling your kid that they "could have done better" is not the same as telling them they're a failure.