I strongly suspect that video was staged. The guy was very familiar with that stretch of road and is a too-skilled rider. His use of "hanging off" to compensate for the bike's lack of clearance shows some ability beyond the average rider.
On unfamiliar road, nobody can ride at 100% because they have to have a bit of cushion for the unexpected. If not, they'll be going off road at some point.
As far as the comparison of street racers to real racers is concerned, it's a whole different environment. Even within racing disciplines there are huge differences in strengths and weaknesses. ISDT riders have different skill sets than motocross racers though there is certainly some overlap. Desert racers see things differently the oval track racers.
Even within a given discipline, riders have strengths and weaknesses. Conditioning and the ability to maintain concentration often makes the difference.
In the end, regardless of his background or identity, the guy can ride. GD
