Pretty much standard. Many hotels (if they aren't a dump) and all airlines charge extreme fees to those who insist on imposing their pets on others in semi confined spaces. They have to price it at a point where the dog owners are more important than regular customers to make it worth some other customers being disgruntled about it. Only pet in the world where you're forced to deal with them if you don't like them. No one is imposing their pet cat, mouse, spider, gerbil or snake on you if you don't like it.
And all they have to do to get them to pay it is make the fee less than it would be to board the dog.