There isn't a wide spread problem of people walking into gas stations without shirts and shoes, so why is there a no shirt, no shoes policy?
You need to look at this from a business standpoint. Why risk the liability of someone getting bit so that 20-30 people can be happy they can bring their dog?
Again, I love petting a nice dog and have no issue with them being there, but if I'm a business, I'd definitely not allow them. From the Fargodome standpoint, it makes sense. Whether or not it makes sense to you as a fan, does not matter.