And you are hijacking a thread that is looking to gather facts about the frequency with which players that have dropped cargo have still been killed by pirates, or pirates that have been given cargo and still chosen to go the kill. You are hijacking by offering your opinion on the practice, as this is not a topic that is framed within the question and IMHO the logic behind your argument is flawed.
You are talking about an open game, where players are free to make gameplay choices, they can choose a style that stays within conventional ethical, moral or political norms or choose to play in a way that goes outside of those boundaries, however there are no wrong choices, players have the freedom to choose. As soon as we start laying down rules to say that only one approach is correct the game stops being the open experience that people bought it for.
Incidentally, should you allow someone to blow up your ship rather than give them some of your cargo you will find that all of your cargo will end up floating around in space and the person that killed you will be able to scoop up the juciest picks from your ship, leaving you to recover the costs of your insurance and lost cargo through more trading. But when it comes to logic over principles, I guess logic never wins.
Personally I only started playing on Open servers after the game was released, I've not really played for many hours and have only encountered one human player and that was by design, we both flew to a specific location and then had to log off and log back in again in a private group so that we could fly together.
I have been interdicted a few times and each time I managed to kill the NPC after waiting for it to attack me first. On one occassion the NPC spent about fifteen minutes issuing threats about how he was going to kill me but as he never opened fire and was clean in that system there was very little I could do other than go into super cruise and dock to sell my cargo.