This isn't the first time that this issue has arisen on FT. While it is true that there are USN's with valid ESTA's, the most likely scenario is that one is a citizen of the UK, obtains an ESTA, later obtains US nationality and is now a USN with an ESTA.

But, this issue about the ability to obtain an ESTA as a USN if one truthfully answers the question seems resolved.

This does not leave one stranded overseas in perpetuity nor does it counsel violating US law even though it is not enforced.

A USN can't be denied entry to the US. It may just take longer because nationality will need to be verified and the primary means of verifying nationality would have been the passport which OP did not have it with him. People return to the US from overseas having lost or had stolen their passport with some regularity. They aren't all sitting in the sterile area outside (inside?) CBP.

Thus, the temporary passport-replacing document is a hassle-reduction device not a necessity.

In addition, the fact that one can make it into the US if one presents oneself to CBP does not mean that all of this is acceptable to an air carrier.