Two things led to this tragedy and both show the future of policing in North America is not going to be a good one. 

The first is the adoption of the aggressive, confrontational approach to policing. The yelling at anyone who has called for the police's help: "Stand back!!!! Stand back!!!!! Arms in the air!!!!!!" 

And the second is the hiring of culturally inappropriate individuals for this role. At one time, to become a police officer you needed to be an upstanding citizen with no criminal record and embrace the values of a law-based society. This particular officer was a Muslim refugee who had expressed foul views on women and was not suitable for handling calls where women were at risk. The practice of hiring at airports, events and venues of Muslims needs to be questioned for many reasons, including their values and ability to provide security in a diverse society and also the known presence of links to terrorists (as we have already seen attacks by Muslims working in security).