The story behind the video:
The two still go at it full bore today. After Kang played self-described "Wi-Fi" golf, missing wildly in both directions in San Francisco but with her short game carrying her to a T-5 finish at the LPGA Mediheal Championship, she and Harmon went back to work. In frustration, as she worked to get her swing back to neutral, Kang threw her club at one point. In response, Harmon then threw one himself.
“He said it's [her club throw] pitiful,” Kang said. “He's like, ‘Let me show you how to do it.’”
https://www.golfdigest.com/story/danielle-kang-butch-harmon-2021-womens-pga