You might be a bit slow, but once again, how in tarnation do people that spend their entire careers going door to door, yard to yard on a DAILY basis ever survive without shooting dogs to death? Like postal workers, UPS etc...
I have seen my fair share of startled postal and UPS workers. Most of them have the same route day after day and they get to know the dogs pretty well.
Some avoid them at all costs, others carry treats for the “good” dogs, and others carry mace.
But the reality is most of them have a route. Often when I work with dogs on the real-life situation the postal/UPS workers get to know me and the dog. It gets to the point where we wave at each other, they often know the dog by name, and sometimes they’ll offer treats.
BUT, the big thing is to realize most of these route type workers see these dogs routinely and know when the dog is out of sorts and the dogs get to know them. Example: I recently had two little yipper Maltese out and about. The one barks at everything, which sets the other to growling and has bitten. They know the mail lady, but the mail lady was walking up the driveway, not in the truck...don’t you know the two went ballistic. Yes, they were on leash, but they put on enough of a display to startle the postal worker.
Contrast that against a LEO who is showing up and is a total stranger. Common courtesy if you had a new friend visiting you for the first time, you would be sure to have your dog under control. Why not when an officer is responding?
Based on what little we gain in information from the dashcam, the dog breached the truck bed to go after the deputy. Instead of asking me to explain the anecdotal evidence of your life experience, why not apply your experience to why the dog acted up towards the deputy and not the UPS driver?