Did they all know that you would be bringing the dog? Was there someone there who is allergic to dogs, or who has a fear of them? Some people can get an asthma attack or other allergic reactions from being in an enclosed space with a dog, and others are scarred from experiences with dogs - you might be sure your dog is friendly and harmless, but they might not, particularly as you hardly know them..
I am very much a doggie person, but I'm not keen on the current trend for having them in eateries - for one thing if there are two of them they might fight, and because not all owners are sensitive to the needs of others, letting them sit on the chairs or even walk on the tables.
I sympathise, and I would have thought that someone would have agreed to sit in the dog zone with you, but if they all thought they were going out to eat in the restaurant and it was you who changed the game at the last minute then I have some sympathy with them, too.