You don't know that he's racing in the video. That was probably a practice lap, where the goal is to get a feel for the track and bike.
You'd feel like a real fool if you pushed it too hard on the practice lap and wiped out before the race even started.
(I know, because I was the pit crew for a kid who did exactly that.)
(I fixed the bike, put him back out in time for the race, and he crashed on the first lap!)
Fred