The "utterly impossible" quote may have been picked up by Milton from the Internet, which earns him a demerit. However, if you bother to read Newcomb's 1903 article, he clearly believed that heavier than air flight
was impossible in the foreseeable future. For example:
"We cannot have muscles or nerves for our flying machine. We have to replace them by such crude and clumsy adjuncts as steam engines and electric batteries. It may certainly seem singular if man is never to discover any combination of substances which, under the influence of some such agency as an electric current, shall expand and contract like a muscle. But, if he is ever to do so, the time is still in the future. We do not see the dawn of the age in which such a result will be brought forth."
"But I do think that success must await progress of a different kind from that of invention."
"But we have already seen that there is no mechanical combination, and no way of applying force, which will give to the aeroplanes the flexibility and rapidity of movement belonging to the wings of a bird. That this difficulty is insurmountable would seem to be a very fair deduction."
"If, therefore, we are ever to have aerial navigation with our present knowledge of natural capabilities, it is to the airship floating in the air, rather than the flying machine resting on the air, to which we are to look."
So what was the context?
I think a fair inference is that, while some of the SciAm staffers may have had an open mind toward the Wright Brothers' achievement, the editors of SciAm did not. Or are you challenging the accuracy of Milton's quote from the January 1905 SciAm?
"If such sensational and tremendously important experiments are being conducted in a not very remote part of the country, on a subject in which almost everybody feels the most profound interest, is it possible to believe that the enterprising American reporter, who, it is well known, comes down the chimney when the door is locked in his face -- even if he has to scale a fifteen-storey skyscraper to do so -- would not have ascertained all about them and published them broadcast long ago?"
What is your evidence that they were coy? According to
http://www.wrightstories.com/history.html --
"First Flight News: When Loren Wright presented the telegram from Orville and Wilbur describing their first flight on Feb. 17, 1903, the editor of the Dayton paper didn’t publish the news because he didn’t he didn’t see anything significant enough to publish."
Profound, and a great way to elevate the discussion.