I frequently see naice looking middle class and "young professional" dog owners not watching their dog - the dog is 50metres behind them - and not seeing it poo. When I catch them up to tell them they try to deny it was their dog or say "I'll pick it up later" which they don't. Maybe they think their dog never poos.
I do also see intimidating looking men with tough dogs and people from the local estate leaving poo, but it's definitely not just one demographic.
When I do see owners picking up poo they fairly often look at me before they do, so I do wonder if they are only doing it because someone is there. Not all owners obviously, but some. (Or maybe they have seen me watching them out the corner of my eye!)
I'm sad that my toddler has developed a real eye for dog poo and shouts "poo! Watch out!" whenever we pass one, obviously learnt from me. When she was younger we had many a walk spoilt by dog poo. The time she got it on her coat and hands and we had to drop into a friend's house to wash asap. Or when her new wellies got covered in it and I had to leave them in the garage as I couldn't get it all off with her crying hysterically and trying to grab them back. I find it in the children's playground where dogs aren't even allowed.
Even when I see responsible owners picking it up it often leaves a smear on the pavement especially if soft poo. Often the pavement is covered in these smears and you can't avoid them with a pram (or wheelchair).
I really think dogs pooing where we walk is disgusting. I read that guide dogs are trained to hold their poo until in a certain place, it would make sense to buy breeds that can be trained like this if you want to walk your dog in a residential area. In Japan years ago I saw dogs wearing nappies in cities which I thought nuts at the time, but now it makes sense. I just don't see how it's acceptable to have smelly poo that can contain harmful parasites where people regularly walk.