Thing is, as long as they're on the leash, they can only do their business within the reach of the leash... But, you seem to have misunderstood the metaphor of

Thing is, as long as they're on the leash, they can only do their business within the reach of the leash... But, you seem to have misunderstood the metaphor of the headline: This isn't about people going to the loo within the reach of some other leash -- it's about how the lack of public restrooms is the "leash", tying people to within reach of a restroom. With restrooms becoming ever fewer and farther between, these people can only move within ever shrinking circles.