I mourn the death of the innocent police officers. I also feel very sad for the 4 innocent people seriously injured in one of the other recent incidents (3 sisters and the child of one of the sisters, all on their way to the airport for a family wedding)>
I don't celebrate the deaths of the men in the Passat or rejoice in it because I'm not emotionally invested enough to have those strong feelings.
Using my head rather than my heart, I think it's a shame that young men's lives were wasted and that the potential they had as babies has been squandered. I also think that looking at the lives they were leading (crimes included racist elements and assaulting police officers as well as crimes against property) and at the trajectory which they were likely to follow, then their deaths are no great loss to society.
If I had the misfortune to live on one of the estates blighted by their behaviour, and was one of the many ordinary, decent people trying to get on my with life and to avoid being on the radar of criminal families, then maybe I would quietly feel that their deaths were a cause for celebration.