I just think some owners are a bit dippy, they aren't aware that dogs cause a lot of issues for wildlife. Ground nest birds will abandon their young, foxes and badgers will abandon their dens, rats and mice will relocate into people's gardens and houses, squirrels and birds typically avoid dog heavy areas too.
There are a lot of parks in the area that allow for unleashed dogs, so it really makes no sense to ruin the lives of other animals because the owner simply cannot be arsed.