This isn't so much about dog owners in my opinion, but more about professional dog walkers, who do it for monetary gain. Many of whom have no real experience of walking or controlling dogs at all.
I actually agree with this. Even in our small village we have a number of unlicensed dog walkers, several of whom I've witnessed trying to walk far too many dogs at one time, and unable to control them. On one occasion a friend's dog got off the lead, ran away, and wasn't found until the...