This was added afterwards after some outcry. It's annoying that YouTube doesn't notify whether the video was edited after the fact, like Reddit/Hacker News does.
That is sneaky. At least they decided to update the video. But overall it's pretty disappointing. Mark is playing this meek, super nice guy persona on the screen. It's just camera play acting to attract young viewers. Oh well, it's good to know. Thanks for mentioning it.