All they have to do is take a credit card for the reservation and charge a fee for no-shows. I would not go to a nice restaurant like that if they didn't take reservations. Most people need to make plans - babysittters, etc.
I understand your point and I can agree with your choice to find somewhere else to go that will accept your reservations. That's the beauty of having the freedom to make intelligent choices based on our own unique needs and preferences.
For me, it's really not much of a problem on reservations, I just plan around it. Most places rarely even have a waiting line at 4:30 PM. I go early, get seated with no problems, and watch the place fill up while I get good service by dining before the mad rush. quite often when I leave, I check out how long the waiting line is and smile knowing I beat the mad house dinner rush and probably got better customer service as a result.
I've even showed up on a Valentine's day at a place with a sign that said reservations only. We noticed the place was mostly empty and asked, if they seated us and served us quickly, we would be gone NLT 5:30. They checked their reservation list and agreed to seat us and serve us. We got our food in a timely fashion, enjoyed it without wolfing it down, and were gone in time for them to clean the table and seat a 5:30 reservation table for 2. by letting them know, we weren't going to sit for hours with bottles of wine, they were gracious to accomodate us and get one more couple served that evening.