anonforthis,
But the US census does not count only the Jews, nor is it conducted by a Jewish king.
And what makes you thing this point changes how halacha treats the count?
It is unlikely that the Yidden were not counted at any time during their time in mitzrayim or bavel
You are making two possibly fatal assumptions. One, that this in fact occurred; and two, even if it did, that it was the correct thing.
(I note these points without taking a position on the primary issue under discussion.)