There is a lively debate about whether or not cops are routinely shooting unarmed citizens because there are so many guns on the street they constantly fear for their lives. I'm sure there's some truth to that.
But really, the problem is many police think they are in a war with the citizens and any interaction that does not result in citizens reacting with total and instant compliance is a lack of respect for their authority.
The police had responded to a dispute between neighbors. As you can see in the video a family dog with a wagging tail came up toe the officer and he pulled his gun on the dog. The dog's owner ran up to stand between her dog and the officer, the officer threw her to the ground and then arrested her.
Police shoot dogs constantly despite the fact that there is no record of a police officer ever being killed by a dog.
They don't even bother to keep decent records of humans being killed by police so they obviously don't keep records of police killing dogs. But there have been many incidents reported in the media. Like this one. And this one, which was particularly egregious:
The Berwyn Heights mayor's residence drug raid was a controversial action taken by the Prince George's County, Maryland, Sheriff's Office and Police Department at the home of Berwyn Heights mayor Cheye Calvo on July 29, 2008. The raid was the culmination of an investigation that began in Arizona, where a package containing 32 pounds (15 kg) of marijuana was intercepted in a warehouse, addressed to the mayor's residence. Instead of intercepting the package in transit, the police allowed the package to be delivered. Once the package arrived at the house, a SWAT team raided and held the mayor and his mother-in-law at gunpoint, and shot and killed his two dogs, one while it attempted to run away.
The event gained national and international media attention. While the Calvos were cleared of wrongdoing, the police were accused by the Calvos and civil rights groups of lacking a proper search warrant, excessive force, and failure to conduct a proper background investigation of the home being raided. Despite the criticisms, no action has been taken against the officers or their respective police departments. In August 2010, Sheriff Michael A. Jackson stated that "We've apologized for the incident, but we will never apologize for taking drugs off our streets. Quite frankly, we'd do it again. Tonight.
This is what we commonly refer to in America as "freedom and liberty."
So, yeah, I'm sure all the guns on the street are a factor in the way the cops respond to perceived threats. But I think it's clear that police attitudes are a huge part of the problem.