Not a "city slicker" by any means here. But, there are times and places for everything.
If I were boomdocking in DJ's photo, I would accept the poo as part of the environment. The same is true for State Parks that have trails marked for horses! But when the campground clearly posts, "No horses in campground" and the riders blatantly disregard and then leave the mess after their horses, well ... that's quite a different matter.
There are several state parks in Indiana that have a horseman's campground and then they also have a separate campground for everyone else. Deem Lake State Recreation Area in Southern Indiana is a Horseman's park. It's set up and designed for the horseman. The horseman campground is .. well ... very impressive! With enclosed stables and everything. Yet, even there, they have signs posted to keep horses so many feet from the lake. When asked why it was posted, it was explained to me by a DNR guy so their poo would not leak into the lake!
And funny, at horseman campgrounds, it seems everyone pick up after their horses. They have these big wooden bins where they dump the poo. I see campers with their rakes and shoves picking up all the time. But!!! in a campground clearly marked NO HORSES! I think that get's back to the very premise of this thread to begin with ... some people are just absolute jerks, thinking rules and common decency doesn't apply to them! Horses or dogs.