Dangerous to their physical health or their mental health? There are a LOT of points in there, that he's trusting other drivers not to suddenly change lanes, or other things they are within their rights to do (Under standardised Australian Road Rules anyway, that video looks like it's shot in the UK somewhere).
Saying he's not doing anything dangerous, is a bit like saying suiciders who jump in front of trains aren't harming anyone else. I read a stat ages ago like 80% of train drivers who kill a suicider, aren't back at work after 12 months.
I've been riding motorbikes for nearly 20 years now. I've found there's two types of riders who think they are good - Those that can control their bikes at high speed, and never make mistakes... And those that know the stupid things other drivers do that make perfect riders crash.
The first group tend to lose members. The second group don't.