GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Unfortunately, when one side starts doing it, the other side will most often respond in kind.Look for the video of the Battle of the Bismark Sea. Lots of Japanese being machine gunned by various RAAF and USAAF aircraft. When the Japanese or Germans or Italians did that it was a war crime but history is always written by the victors who always develop amnesia.
The Imperial Japanese did not have the best track record for assisting shipwrecked people from the very start of the war.
Many examples of direct orders from high command to "totally eliminate" enemy assets: ship, cargo and crew can be found.
The IJN's I-37, was the leader in carrying out their orders and among their unfortunate tally, was the Australian Hospital ship Centaur.
The incident of strafing survivors at Bismark Sea was done by both sides, like the Japanese who, during the early days of the battle (3 March), strafed 7 survivors of a damaged USAAF B-17 (piloted by Lt. Moore) who were in the silk.
So in the end, no one was guilt-free.