Nikon is bullshitting you. Fact.
You defend them. Fact.
You feel that I have no right to say it. Fact.
You feel hurt because I revealed you are being bullshitted. Fact.
Frank, I think you are putting the proverbial horse before the cart (haven't we talked about horses already?).
First, you have to provide some evidence for the hypothesis that Nikon USA's gray market policy is not being enforced (above bold-faced statement).
After that, we may talk about interpretations or possible reasons (marketing strategies etc.)
So far, I have not seen any evidence for the hypothesis in question, and I find it appropriate that people object to your conclusions.
Especially if you have experience with marketing yourself, you have to be open to the possibility that your above-average familiarity with the subject is yielding an above-average rate of false alarms (i.e. you smell marketing BS, but it is in fact a real policy with enforceable consequences).
Jumping straight to conclusions (i.e. I smell marketing BS, therefore it must be marketing BS) will therefore net you a high rate of false conclusions.