It's rather odd that it took so long for an East Asian to win a major championship, because East Asians were runner-ups in 1971, 1980, and 1985 (when T.C. Chen needed to hole a bunker shot on the 72 hole in the U.S. Open to force a playoff -- I was standing behind him at Oakland Hills in Michigan and couldn't see the hole, but could hear the thonk as the ball struck the flagstick, then saw Chen whirl around in regret as it rolled away from the hole). Looking at that trendline for second place finishes, you'd figure there would have been an Asian winner around 1989, but instead it took 20 years longer.
In contrast, Continental Europeans emerged as contenders in this Anglosphere-dominated game at about the same time, yet quickly broke through as champions.
South Korean women, like Swedish women, have done very well in ladies' golf, but that's mostly because those two countries invested a lot in training girl golfers.
So far, there's no particular pattern of any race being better or worse at golf. Success largely depends upon starting intensive practice at a young age. Malcolm Gladwell talks about how it takes 10,000 hours of practice to be great at anything, but to win a major championship in golf typically takes about 20,000 hours. For example, it took Tiger Woods 19 years of playing and Phil Mickelson 32 years. The shortest period between taking up the game and winning a major was Gary Player's seven years.