Of course the rockets are heat seeking. But someone has to give the order. They have sensors, they investigate. They report up the chain of command. I don't even want to know how many people were involved from the moment it was detected to the moment the order was given. 100? 1000? More? And no one bothered. And the US weather service alone starts around 60,000 to 100,000 balloons a year.

It doesn't matter how you FIND an object if you can't target it. That's why articles crying that china can track the F22 and F35 are meaningless, because knowing something is in your sky and being able to direct a munition into it are very different things. Pilots who have practiced dogfighting the F35 have expressed surprise at just how close you can be and still be unable to get a good enough radar return from the targeting beam to actually shoot at it.