The Journalist targeted a drone at long range and burned through the body. Make the drone closer and select a less beefy component such as a rotor arm and they go down quicker. BTW if you didn’t catch it in the article maximum effective range is well over 1 mile.
You also have to remember the US Military also isn’t going to allow a Journalist to publish the full capabilities of a fancy new future-tech weapon like this. Gotta leave some surprises in place!