Luftwaffe pilots shot while parachuted

[GuerraCivil]

The attacks on parachuted pilots seem to have been quite common. I wonder if it would be the logic on war to accept them as "logical" when one considers all the cruelties happened during WW2 and other conflicts? Thus making the chivalrous behaviour the one which is the "strange thing" in wartime and worth of psychological analysis: is cold-blooded killing or hate motivated behaviour more logical and understable than to spare the life of an enemy and letting him to parachute in safety?

Besides attacks in air, some parachuted pilots were shot from the ground when they were descending. Of this I know well documented cases during Spanish Civil War committed by both sides. Sometimes even own airmen were killed with the assumption that they were enemies.