It isn't an onslaught, it is a lot of statements by individual people that they very much dislike having dog-shit on their property - even if the solid lump of it has been picked up by the dog's owner and disposed of responsibly because a smear of it is always left behind. If the area is hardstanding it can be washed down but not grass. Strong disinfectant doesn't disguise the smell to other dogs with their sensitive noses, so they will reuse that spot. Why do you think dogs often sniff around a spot just before defecating?
The other reason to avoid soiling private lawns (and at a minimum, play areas in parks!) is the health risk. Someone posted that only 120 cases of toxocara infestation a year in humans were recorded - but a quarter of humans were found to have specific toxocara antibodies - which means that they came into close enough contact for their bodies to react. Why would you want to risk the horrific results on children?
Most non-owners like dogs, and most dog-owners love their pets and take care to have them regulaly vaccinated and wormed, and trained for the dog's own health and happiness. However some forget that the dog is also interacting with the rest of the community. Parents have to consider this with their children, parents of furbabies are no different. If so many posters find dog shot so revolting and offensive, surely offended dog-owners can take that onboard?
The time to toilet train (indoors and out) is when the dog is a puppy and just learning what is acceptable. Once they have a pattern it is harder to retrain them. I am surprised that professional trainers don't publicise more the dangers and unpleasantness of random excrement.