If we assume the result will generally be packs with no fear of man, particularly if they're aggressive toward man, that would be unacceptable, but I don't think that would be the case. First and foremost, I've encountered plenty of stray dogs and almost all of them had a well developed fear of man; man has a way of justifying animals fears to an extent that even animals normally more likely to be predator than prey still prefer to avoid him. Even when an animal does not actively fear man that does not translate into aggressiveness. A dog whose history with man has been unpleasant will seek to avoid man out of fear, and a dog whose history has been pleasant will seek mans company, but in neither case is the dog likely to be aggressive or violent toward man. Dogs trained to be aggressive will remain so, but that's true whether the dog is a stray, a pet or simply treated as a weapon with an owner; the threat there is not in stray dogs, but in dogs trained to be vicious, and no action involving the stray population will appreciably affect that threat.

While it's true that a catch and release approach would result in far more loose dogs, it's also true that the current number of loose dogs is more than adequate for strays to form packs, yet I don't believe it's the norm (I've certainly never observed it). Pack hunting like wolves is usually unnecessary, and the instinct has been bred out of many breeds anyway. The dog remains social, but the social instinct is often almost PURELY social rather than a survival instinct. Because dogs do not normally stalk larger game like wolves anymore, maintaining a pack can actually compromise survival; when food need not be killed but is scarce a pack offers few advantages but can easily stretch limited resources beyond the level of subsistence. I suspect that's why I don't see strays in packs; it's hard enough for one dog to find enough discarded food to survive, let alone for five dogs to do so in the same area.