Doesn't the society that produced those very specific killers (officers in uniform) deserve a look?
Of course. And don't forget they aren't part of some insular, separate society. BLM, the right-wing extremists, the left wing extremists, the people with moderate views on all sides, the religious, the non-religious, the protesters, the police, the government, all who vote or don't.....they're all part of the same society.
They all have an influence on each other.
The policies put in place by the people you and I vote for have effect on all of us.
Thinking otherwise would be silly. It would also be dangerous, as it would give one the idea that the problem is caused exclusively by 'the others'. It would stop them from looking at society as a whole and working together to solve the issues society faces.