Here's the thing, the Dev has already said it is not an exploit, continuing to call it an exploit and saying Dev's just don't get it is not going to win them over to make the change; and threatening to leave the game has never been a good arguement.
I'm not sure how responsive the Dev's are since I was not in the Beta, so for me this is the start of a long relationship, and I think if we can present reasonable arguements (for both sides) that the game will be better in the long run.
Likely this thread has gone on too long already to be useful, but I'll try one more post.
The transport driver loses the load either way, so the specific issue is that the driver can deny the pirate a tangible reward by deleting the load.
If the solution is to remove the ability to delete items from cargo, I'll support that because just giving the driver the ability to rage-deny the pirate doesn't really promote more players to get out there and PVP; which even though I don't, I understand that it is the driving force behind the game.
But, the ability has to be removed, not just modified to prevent a case specific action. Removing the ability to delete cargo items isn't going to break the game, it will however make other aspects of the game more difficult to play, such as farming.
I believe that giving the players more options is always a good thing, taking the delete function away removes an option, and reduces the need for player interaction. If all the combat player wants to do is blow stuff up and get loot there are NPC's for that.
But, as I said if combat pilots are willing to give up the ability to delete items too, than I'll support that.