Maybe they're thinking if they kill the hostages, the criminals won't have any leverage and will surrender. (/s, sorta).
Like just after 9/11 when people finally realized that sitting in their seats and waiting for negotiators wasn't going to get them off the plane alive. Maybe nothing would. Being take hostage isn't much of a future any more.
But apparently, police, rather than robbers, killed the hostage. With the contemporary paradigm in the justice system, many are taking revenge and committing planned suicide—a trend that judges of the past warned against. Even remedies in civil cases have become so outrageously expensive and sometimes unobtainable, that matters will more often be settled outside of courts.
Since many influential constituents want to move on toward an apathetic and fuedal society, we have no choice but to watch it go to its consequences for them.