I had no problem with a dog on his property being protective, it’s his job. I do have a problem with a dog that comes from another property to get to me.
The problem begins when suddenly a dog decides that YOU are it's "job."
I have seen dogs overcome and endure tremendous pain (way worse than an electric fence) if it is sufficiently motivated to do so. And that motivation doesn't need to make sense to us.
Also, dogs have a very different notion of "property" than we do. And it doesn't necessarily include the dog owner's property lines or fences.
There have been times and circumstances when dogs are my friends. However, my numerous experiences in the role of a courier, dogs are NOT my friends.
Not at all, not one bit. (pun intended)
And I think the pink, well-fed suburbanite needs to suffer a week in an Amazon van for his "screening their workers" comment.
I'll tell his wife to buy life insurance for the inevitable result, and then help her spend it after he succumbs.