@GammaX6 We're in total agreement.
I think you missed the fact that I'm the OP and that I flat out rejected the so-called solution. I also pointed out (replying to @DeiSasori) that I think we're being ripped off here by EA.
However, I don't think it's a malicious, intentional or unsolvable problem.
I imagine that faced with the issue of preventing propagation of the DLC to ineligible users, someone at EA apparently decided that restricting the content to the main account is a good enough solution. I think they failed to realize that this game is played by many kids using sub-accounts (see many examples on this thread) and that this "solution" is going to * off many people (parents and kids). Also, some of us have multiple kids (each with their own sub-account) playing the game, making a solution in the form of delivering the content to just one (or the first) sub-account worthless as well.
My rather lengthy (and apparently unclear) post above was meant to point out that the problem isn't really a technical one. It's a simple enough matter to also restrict the content to the sub-accounts managed by the main account that purchased the DLC.
I'm frustrated as well, as I'm sure many others are: EA need to issue a patch resolving the issue instead of insisting on their obviously broken solution, and no, pointing out the restriction on PSN doesn't cut it, sorry.