I think what the airlines charge to have a dog is really wrong... but I still pay. Why? Because I am not willing to suffer the consequences if I get caught not paying. I do not steal, I do not cheat, and try not to lie, but to charge for a dog when the dog is not taking space or changing anything that is happening on the flight is their way of making money I guess. It is my choice to pay or not to bring the dog.
Now... I agree with checking for shots (I think it is only rabies) and limiting the number of dogs on a flight due to algeries of other passengers.
When I book.. I book the dog too.. I am not too sure I would remind them of the fee if they didn't charge me lol.. but knowing me I would be afraid not too