When my son was diagnosed with autism, I decided I would never judge the parenting skills of others. So many things can be going on, which the casual observer is unaware. Especially when my DS was younger he would melt down and go into a full scale tantrum. I had to endure the glares and mumblings of people who had no clue about our lives. So while trying to calm my child and neutralize the situation, I was humiliated by others. Those early years were particulary difficult.
However, I have always removed my son from a restaurant, movie theatre, church service, etc. any situation in which his behavior may impede the enjoyment of others in the environment. I have spent many evenings in the car or walking outside while DH finished dinner with other DS and brought remains of our dinners in boxed containers. For quite a while we didn't even go out as a family. DS now can sit through most meals if he is seated in the proper location and we use other stratagies we have learned over time.
Likely the family the OP encountered was a typical family, but one just can't know what is going on in someone else's life. For that alone, I would never presume anything about anyone. Having been a victim, I won't do it to another and will suggest that others should follow suit. JMHO.
The comments about kids' manners did hit a nerve with me. DS is 8 years old and doesn't always use silverware. He mostly has to use a spoon. He certainly doesn't eat with his face in his plate, He tries his best and gets help from not only us but his Occupational Therapist. So, I hope if you see him pick up a green bean with his fngers, he won't be put in the category of farm animal at the trough. Actually, I believe his manners are better than many, especially those that demonstate respect and consideration of others. Again, a quick observation can not provide a fair assessment of a child or his/her parents.
Getting specifically to the complaint of kids disrupting meals. What are you going do? It's going to happen. It's annoying, yes. It is ridiculous to think that all families with kids should be segregated to one area. Those of us who have worked for years ensuring that our children will behave in a way that doesn't disrupt others shouldn't have to sit "the kids' table". We want to enjoy our dinner, too. As far as specific hours for seating with children, I agree with a pp, that isn't fair either as some parents have their children nap in preparation for a late night. Just because there are a few tables with disruptive children, doesn't mean that it should be assumed all tables with children will be that way. However, I think it is FAR more likely that you will encounter it at WDW. If it isn't tolerable, then I would dine elsewhere. The odds of having a noisy child at a fine restaurant not on Disney property must decrease significantly. Now, we could address rude adult behavior as well, which I find just as annoying: people using cell phones at dinner, obnoxiously loud people, people snapping and demanding things of servers...There will always be something that CAN take away from your dining experience, ITA with a pp that suggested focusing on the positive aspects.