I don't think most people mind when a restaurant sells the moral equivalent of tickets to dining slots ahead of time. I've visited restaurants that do that, and had no problem with it.
The issue is that you were taking something that was free (open reservation slots), and then forcing people to pay for them if they wanted to dine there... when they could have just made a reservation -- perhaps farther in advance -- for free.
I agree that most people in the restaurant business aren't in it for the money (if they are, they've picked the wrong industry). But scalping reservations to their restaurants is making things worse, not better.