riplin@Azonic.co.nz wrote:

In 1947 americans were particularly paranoic (has it changed?)

Further to that:

"""NEWSWEEK ran an article titled "Balloon Mystery" in their 1 January
1945 issue, and a similar story appeared in a newspaper the next day.
The Office of Censorship then sent a message to newspapers and radio
stations to ask them to make no mention of balloons and balloon-bomb
incidents, lest the enemy get the idea that they had a good thing
going."""

Perhaps the Roswell paper thought the ban was still in effect so it
didn't mention the balloon but only the equipment canister suspended
below it.

"""The fact that the balloons had been launched beginning in the fall
made them little menace. The incendiary bombs could have caused forest
fires, but by that time of year forests were generally too damp to
catch fire easily.

However, the authorities were worried about the balloons anyway. There
was the chance that they might get lucky. Much worse, the Americans had
some knowledge that the Japanese had been working on biological
weapons, most specifically at the infamous Unit 731 site at Pingfan in
Manchuria, and a balloon carrying biowarfare agents could be a real
threat. """

Maybe the military reacted because they thought the US was under attack
by balloons again, perhaps from the USSR.