It seems you're overstating the case. When I click through I see causes of death like "heart attack" and "automobile crash". Other people die of those causes as well.

Policing isn't even in the top ten most dangerous jobs. Save the honors for fishermen and lumberjacks.

Full data. I'll let you decide which deaths count and which don't.

    Total Line of Duty Deaths: 147
    9/11 related cancer         24
    Accidenta                   l1
    Assault                      3
    Automobile crash            22
    Drowned                      1
    Duty related illness         2
    Explosion                    1
    Gunfire                     48
    Gunfire (Inadvertent)        2
    Heart attack                19
    Motorcycle crash             1
    Struck by vehicle           14
    Training accident            1
    Vehicle pursuit              1
    Vehicular assault            7

They shoot-to-kill anything that they feel like threatens them. I can see how that might keep them pretty safe.