It's all fun & games until somebody gets killed.
There are quite a few pilots who are both old & bold - they merely represent a statistical minority. For the same reason, there are quite a lot of people who smoke and don't get lung cancer; increased risk is not the same is certainty.
However, straight & level flight at very low level is actually pretty safe provided that you're higher than the height of your landing gear because you can get an idea of the picture from the cockpit whilst you're still safely on the ground.
In this case, the first aeroplane flies by at roughly gear height - compare with the picture
on its Wikipedia page.
The foolish part of this video is how close he's decided to take the aeroplane to the spectators, rather than the height itself. People are unpredictable, the pilot has no real idea what his downwash and jet blast are doing, and of course showing off for the camera is tantamount to testifying for the prosecution. Given that everybody and his dog has a cameraphone these days, showing off within sight of people equates to showing off for the camera, so even if he didn't know that people would be filming,
he should have guessed...
In the absence of "innocent" bystanders, it gets "interesting" when people start flying lower than gear height, at high alpha, or with bank on, because there is no real scope for safe rehearsal.