They feel as though the world is ganging up on them at this point even when they are the ones whove done nothing wrong.
As long as the thin blue line still exists, many of the "good" ones have done something wrong. Maybe not as egregious as others, but by defending, lying for, or ignoring the problems, they are compicet.
People come up to them daily and call them bad people because a shitty officer in another state has committed a crime.
Many have by lying under oath, covering up internal crimes, falsifying evidence, and not reporting the bad ones.
Now they see a guy with his hands in his pocket who isn't responding and they have this mentality that all these criminals are out to get them.
There are other similar cases also. There is a problem in the police forces of the country that needs addressing.
The officers are afraid they won't be coming home to their family tonight
No. This is perhaps the weakest origin to take. For starters, they choose this field of work. They knew the dangers, they knew the responsibility, they knew the landscape of the job. If they claim they didn't, then they are not fit for the job as they blindly stumbled into a job they knew little about. Who's fault is that?
As far as hearing for their life existing the killings and tazings? That doesn't explain the ones shooting old men in the back as he ribs away after a traffic ticket (he was afraid), followed by the cop planting a weapon on the guy lying on the ground, or the cop lying about the interaction.
How about this. I live in a high crime neighborhood (I do), and I see people get mugged and beat up. Since I'm afraid, is it OK for me to go around shooting people because I was afraid? If I were a woman, could I shoot people because I was afraid?
Being a police officer really sucks right now.
While some of this sentiment may be legitimate, a large part of it is the self induced through behavior and attitude that needs to be addressed. Cops have had a different set of law for themselves for a long time, only now is it starting to be an issue because of cell phones. A glimpse into their actions is causing the current landscape, and for that I fault them.