It is not only the amount of fee which matters, what are you paying for matters too. It is ok if fancy restaurant charges more then fast food eatery, but I don't know anybody in good mind who would agree to pay anything just for sitting in a restaurant having no food. It is ok to pay $1 fee for a trade which brings you $5 profit, but paying for an offer which was not even filled is ridiculous. It is not physiological, this is common sense.
Paying for an order which is not filled is not ridiculous. Placing an order has costs associated with it and the cost is significant in every trading system. Some systems just have chosen to subsidize this cost by increasing other fees.
And while you don't necessarily profit from an order that isn't filled (you can, by the way, if you're using it as part of some trading methods), you certainly had the opportunity to profit from it.
Taking care of restroom in a fast food place has also associated costs with it, but if they will start charging fees for using their restroom, then good luck in attracting customers.
Most places make you buy something if you want to use their facilities.
In some shitty slums may be so, but in the world where I live they allow me to use their facilities with no conditions, because they know that if I like their place I will buy something from them and come back again. When I come to eatery, I want to pay for food. Washing hands, using toilet, sitting at the table has to be included into price of damn hamburger. If they don't do this, I turn around and walk away. You have to decide what are you going to be: just another shitty exchange or high quality service.