Horse Poop

I love Riverside State Park. From Mt. Biking, hiking, dog walking, to riding the Centennial Trail. But lately there has been horse poop everywhere! Anyone that has walked across 7 mile bridge knows what I'm talking about. People let their horse's poop anywhere & just keep on going. Put a bag on that horse or stop & clean it off the trail. No one likes riding through any kind of poop. People freak out if someone doesn't pick up their dogs poop. Why do horses get a free pass?