LOMCEVAK:
steep flightpath angles, such as those that occur during a loop, do present a significant risk of impact with what is directly underneath the aircraft if the manoeuvre deviates excessively from the norm.
The problem with flying low and fast over roads, populated areas etc is that the sudden noise may induce accidents or trauma for those overflown and, in the case of roads, provides a distinct distraction to drivers. These considerations are what often dictate the restrictions imposed at air displays.
You get it. Suppose the Hunter had cleared the road at 100 feet AGL, thus meeting the minimums (as I understand them). The people below would have seen a jet diving on them at hundreds of knots, and heard the roar of the engine at full power less than 100 feet above their heads. With the nose high, I wouldn't be surprised if jet blast would be a factor. That's insane. People could have been killed by panicked drivers.
I gather some of you can't grasp how this is very different from routine landings at airports. I greatly doubt jets are passing 100 feet over roads like the A27, but if they are, they aren't diving at full power.