If I may share a relativist observation:
There is probably not a square inch on earth that has not been subject to US reconnaissance since the 50ies several times over, new lava islands that have sprung up in the Pacific possibly excepted, but they'll get to those too in time, no worries.
Still, downing that thing was perfectly warranted - as would have been sabotage or destruction of a US satellite spying over China by the Chinese. The golden rule is: Don't get caught. And if you are, don't be a sissy about it.
In general, espionage is a healthy thing, as long as everyone does it and shares in the results some of the time; it manages expectations of all participants and keeps things in balance. Some of the worst decisions in world history were taken for lack of sensibly procured prior intelligence.
They could at least have painted a dragon on it. Or Dr Fu Manchu.
And I was half-expecting that the US would abduct the balloon intact and analyse everything in some officially non-existent desert underground facility!
