One thing that may speak for more "dog liberties" in Chinese cities than in their western counterparts, is that here badly behaved dogs are removed from the "gene pool" much faster.
Somewhere else, with tighter requirements to keep dogs on leash and played only in designated areas (which are also made available) etc, observing those requirements may result in keeping some dogs (both individuals and certain breeds) as pets that would not survive in Chinese system.
In this perspective, when accidents happen (say a leash breaks loose), results can be worse in western countries.
In China, this risk is smaller so dogs are let go "anywhere they want".
Yes, go ahead and replace "dogs" with "people" in the above comment.