I'm not sure how much I can add to this , as I really don't understand the nuances between early decision, early action, etc. I understand the argument that if you apply for Early Decision , with financing as a condition, then you have the right to walk away. That is a simple legal concept, ie.. a "conditional offer."
That said, the practical application is that if USNA's policy is that you must withdraw your USNA application, then you should comply --regardless of whether you have a "legal right" or disagree with the USNA policy. Sure, you can reach out to Admission and try to explain, but I would caution against "sea lawyering," a term many Plebes learn about the hard way. USNA has organizational commitments, and they will honor those.
The bottom line, the intent of applying for ED is a declaration that the ED school is your first choice and committing to attend that school if accepted (and in the case of financial aid, the condition is met). I don't know if the ED application has a place to identify the financial aid condition, and if not it should . Similarly, the USNA application should include a place to declare whether you have applied ED, and if so where and upon what conditions, This would clarify the financing contingency.
This topic creates a lot of angst and heated discussion every year ... and it is really obvious to me that some "game" the Early Decision process. Sure, there may be legal arguments and ambiguities in the system to exploit. Not going to be judgmental, its things like that that keep us lawyers employed plugging the holes.