Same reason you cannot use a laser sight on a gun, or a flashlight. Same reason some states do not allow electronic sights. Some people think hunting should be kept a primitive sport. Some people think it takes the sport out of hunting, that you already know where the game are, sort of like using a phone or radio to tell other hunters where animals are. It is giving the hunter a better edge...

...or maybe Montana released a Bigfoot back in the 1970's that was created in a lab, and now they do not want anyone to find it. So, they are banning cameras.