Last week, the CNN anchor Brianna Keilar found herself, for the second time in under a week, guiding viewers through the grim ritual of trying, and failing, to make sense of another mass shooting.This time, it was 10 people dead at a grocery store in Boulder, Colo. Only a few days before, she had interviewed a survivor of the rampage at Atlanta-area massage parlors. In 2019, Ms. Keilar reported on the back-to-back shootings in El Paso, Texas, and Dayton, Ohio. In 2018, she spoke with relatives of students killed in the shooting in Parkland, Fla. Broadcast journalists like Ms. Keilar, 40, have now …
