Someone made a sensible comment - “because the “near space” area is a grey zone in international law that is beyond the range of military and commercial aviation, yet too low for satellites, the US, China and other countries have long operated things like balloons there for surveillance purposes. For these reason, the US doesn’t want to shoot down a balloon, which is the result China wants, so they may shoot down one of ours”
OK- possible
BUT if this balloon if operating at below 40K feet, its clearly a threat to commercial and private aircraft. Why shouldn’t it then be destroyed?
The Karman Line is way above where this thing can go. It is not a “gray area”.