I think you need to look at the video as the last straw, not the primary cause for this apology. Kalanick has always acted remarkably immaturely for the CEO of a major company [1], and now Uber has dragged themselves into a total shitstorm with the recent sexual discrimination/abuse stories, and the Waymo/Otto IP theft debacle.

He's just trying to save some face for him and the company in the midst of a glut of PR disasters.

[1] https://pando.com/2014/02/27/we-call-that-boob-er-the-four-m...