I agree with urge to herd on people who attribute every quirk to former abuse. I don't know how many times I have tried (and often failed) to talk someone out of this attitude. People apply it to cats as well. This is simply ignorance; I tended to think that way myself many years ago before I knew better. What seriously irks me are the people who choose to remain willfully ignorant; the dog may very well not benefit from that.
According to an article locally, the CDC estimates somewhere between a quarter million and a million 'rescue' dogs are imported into the IS per year. This because there simply aren't as many dogs as there are people who want them. 'Overpopulation' has loong since been overcome.
That reporter doesn't know everything, nor does the CDC.
It may be true that there are that many dogs being imported by rescue groups. But it is not true that overpopulation has been overcome, let alone long ago.
The animal shelter here receives 50 dogs a day at times, and they don't all get adopted. That is just one shelter in one town in a country that has thousands of shelters. I don't know what that is, if not overpopulation of dogs.
Backyard breeders and puppy mills churn out tens of thousands of ill-bred puppies per year, many of whom will end up on the street or in a shelter due to congenital defects or simply because the person who bought the puppy loses interest.
It is possible that there is no overpopulation in one town or one county. But certainly not overall in the country.
As for the term "rescue", I disliked it at first, myself, and still find that it is inadequate to describe the entirety of these animals. There should be a better word, but there isn't one that covers all of the circumstances through which these animals end up homeless. Some are most genuinely rescued. Some are simply turned in by people who don't want to keep them any more, and have suffered no trauma or danger.
I use "rescue", because these days everyone understands what that means, and it is simple. But I like to point out to people that not all rescue animals come from a bad place or have been abused.