So, we've been here for a few weeks, why do I need my dog on a leash always on leash. But the owners of the campgrounds don't need that? I'm 120 lbs my dog is 72.. its difficult to keep her from killing the small dausch hound

Because they own it.

Having your dog on a leash is protection for you if anything happens. It falls under the leash law. Not all people feel they have to follow the rules even though they're the ones that made them. I have 3 pit bulls one is a 120 pounds I myself like to let them run free but around other campers and other dogs I have preferred to have a Mana leash where I can control it

Because you have to obey the rules.