I understand a higher fee for the cabin/yurt, because someone theoretically comes in and cleans afterwards. It still seems steep, but I guess they can charge whatever they want.
We have 3 small dogs, we bought a camper because we don't travel without our family members. Dogs and campfires are a part of camping, despite the grumps out there that hate both.
I wouldn't object to a $1/night surcharge for dogs if the park provides doggy bags. That seems reasonable to me, although I provide my own bags. Much more than that, I would be very hesitant to pay and would want to know what services are being provided by those fees.