I guess considering I used to work in Mission Control and participate in these simulations, the language used here is something I notice probably more than others.
The simulation itself was broadcast. The astronauts and the sim team were in Houston. The alarm originated from a computer on the ground in Houston. The comm loops that were heard were from a sim on the ground in Houston. This headline would make more sense if NASA was troubleshooting alarms on ISS and configured things such that those messages would be on a private channel but messed up and the public heard them. In this context the fact that it was a sim is important.