I do understand that there are plenty of parents out there that don't manage their kids in restaurants (I've seen them), but I also know that there are plenty of kids out there that can handle the nicer restaurants and behave appropriately (I've seen them too
).
Unfortunately it's the few rotten apples thing. I've seen my share of well behaved children as well as some that are over the top misbehaving. I have no problem with kids in nice restaurants if they can handle it, and if Disney had a better policy for removing disruptive people of all ages.
My 3yr old niece is a very calm kid and can sit there for hours coloring - she's always been great in restaurants. My other niece 2.5 can't sit still for more then 10 minutes - she'd be one of the running/crawling/shrieking kids. Unfortunately not every parent is willing to accept that their kid has limits to what they can handle. It's these same people that think their right to have dinner trumps the comfort level of everyone around them. Common courtesy seems to be dying.