There you're dealing with the cost of growing the frags...running a salwtater tank isn't cheap as you already know. To farm corals costs money in electricity, supplies (salt/water/saws/plugs/etc), and labor. And at the end of the day, they have to make a little money too or else it isn't worth it to be in business.
Oh I absolutely agree, especially when you've got a small number of things or a slow grower... It's a little different when you've got 40 frags of something that's a fast grower and are still asking top dollar, I just find it a little silly. But whatever, they need to make their profits to stay in business, and I can simply choose to not buy a specific item, wait for a sale, whatever.