This is what you're basing your assertion on?
I see a few problems with what you're claiming:
- we have no reason to believe that an image of a simple typewritten letter from a web site that appears to have a very particular agenda is true (though I concede we also have no particular reason to believe it's a forgery either).
- we have no reason to believe that the individual author of the letter had the knowledge or technical background to be certain of his claim. The subject matter of this letter goes well beyond
the stated mission of the USNO, so it's doubtful that they would even have had anyone on staff who would have been able to give an expert opinion on this matter.
- we do not have the original letter and questions that this letter is obviously in reply to. This does not let us see the original context in which these statements were made.
- the letter does not state what you're claiming it does. It doesn't unequivocably state that the weekly cycle is unbroken, only that as of 1932, no articles that the author was personally familiar with stated any particular doubt on the matter. Presumably there were other experts at the time, and other work has been done on this matter since then.
- what claims are made in the letter are limited in scope. It specifically gives a qualifier of "long before the Christian era". Even to a young-Earth creationist, the time span from Genesis to "long before the Christian era" could conceivably be millenia. You're still relying on an unverified chain from God to Adam, through his descendents, to the first people to create an actual calendar, to those who created the calendars that are referred to in the letter.
BTW - the USNO was also the originator of
this map. Do you think it can be completely relied upon for, say, land surveying?