But then there’s the question implied in the report that the shooter was there for at least 12 hours. How is the USSS not constantly sweeping the environment, using drones, helos, etc...?
Time for private security and several body doubles.
But more importantly, they did know the guy was there, and did have him under observation. The moment they saw a weapon, they shot. It doesn't seem to be that it was illegal for other people to be in the vicinity of the golf course, so they had to look out for suspicious activity, which they did. Successfully.
Maybe stuff will come out that makes them look worse -- I'm not making some categorical statement that they did everything perfectly. But at least in the context of the massive FUBAR that was Butler, this was much, much better.