I'm sorry I really do have to put in a word for the amateur pilot here. We are talking about recreational flying. It is a sport. Sport by definition is going to reduce safety factors over slumbering in an arm chair.
We all approach this recreation or sport in different ways. What matters is the extent to which any action is putting others in danger to an unacceptable level. Those of us who fly single engined aircraft where there are people below us are increasing the danger level for those innocent parties. Those of us who carry out aerobatics or formation flying are increasing the chances of something going wrong. Generally we train for it and keep doing it to maintain currency to reduce the danger (and indeed sometimes sharpen us up to deal better with other dangers). Is low flying dangerous?. It depends on how you define it. The law defines it for the purposes of the ANO and possible legal action. Whilst this might be related to danger it does not define the increased danger level (just as making it illegal for a Cessna 150 to fly close to Sizewell nuclear plant does not give an indocation of the level of additional safety risk this creates).
Flying at 50 feet is less safe than at 5,000 ft (all other things being equal). Flying at 501ft is less safe than at 5,000 ft. Where does low flying become irresponsible?. I am currently working up my display authority which will allow me to fly down to 100ft with the full support of the CAA (in certain circumstances during displays or display practice). Flying over open water I have flown at lower heights but have had a heightened understanding of the safety erosion I have created. Why should I bother doing this? Why should I bother flying in close formation, why should I bother doing aerobatics?. It is a sport we participate in not pretending to be mini airliners.
What does the argument that a commercial pilot might be sacekd if he flew so low tells us about this case?. Nothing.
A 737 bound for Palma formating on a 737 bound for Dublin or doing a loop might also raise the interests of the pilots employer. It doesnt make these activities wrong or illegal in a Tiger Moth or Chipmunk.
Now 30ft over a packed beach with nowhere to go if the engine quits is both illegal and unsafe. 30ft over a beach with one person on it within 500ft is illegal - it might or might not be unsafe.
I don't know the precise circumstances of this occurence. I don't know the skill level or state of practice of the pilot so I wont judge.
Ignorant condemnation and extension of blame and criticism to others is a fact of life in forums. Sometimes, however, sensible debate breaks out.
Me I shall seek to continue to enjoy the sport I have spent more money on than I have on my house and will continue to improve my skill level to be able to do more things which generate more enjoyment and excitement.