Looking back on the whole bunch of linked threads sure indicates that Fdev never answered the question and the Forum readers who resist change are simply arguing in a circular manner about why you shouldn't be allowed to do it, feeling that the last time they disagreed was sufficient to close the matter.When people say "search the forum we already answered " it usually means they had a big argument and never resolved the issue
The issue exists right now, not because of any design decision. It exists right now because of a lack of foresight in designing the inventory system. The cargo isn't part of the ship, it is part of the player.
A player IS capable of storing cargo off of their ship if they own a Fleet Carrier (which has its own cargo), so surely whatever feared exploits might happen would be equally possible if a player owned a fleet carrier.
I seem to think the reason why we can't have ship specific cargo is that the FC owners feel that they spent a lot of money to get the privilege and you have to join the club if you want it too. (This argument is consistent with their argument for why non FC owners can't micro-jump)