Surely it is aafer to fly under an obstacle than over it.
Logically if an emergency landing is to be performed then being above such obstacles endangers the helicopter and in the case of bridges all those who are on it at the time unless at such a height that these obstacles can easily be avoided.
However, being under the bridge or wires there is nothing to avoid until ground contact.
Therefore the pilot in the photo was flying at the safest place disturbing nobody, BUT breaking the statutory rules of being closer than 500 feet to .......etc